Solid-state imaging element and solid-state imaging device

ABSTRACT

A solid-state imaging element including: a photoelectric conversion layer, a first electrode and a second electrode opposed to each other with the photoelectric conversion layer interposed therebetween, a semiconductor layer provided between the first electrode and the photoelectric conversion layer, an accumulation electrode opposed to the photoelectric conversion layer with the semiconductor layer interposed therebetween, an insulating film provided between the accumulation electrode and the semiconductor layer, and a barrier layer provided between the semiconductor layer and the photoelectric conversion layer.

TECHNICAL FIELD

The present disclosure relates to a solid-state imaging element and asolid-state imaging device that use, for example, an organicphotoelectric conversion material.

BACKGROUND ART

A solid-state imaging element such as a CCD (Charge Coupled Device)image sensor and a CMOS (Complementary Metal Oxide Semiconductor) imagesensor has been used in a solid-state imaging device. The solid-stateimaging element is provided with, for example, a photoelectricconversion layer including an organic photoelectric conversion material(see, e.g., PTL 1).

CITATION LIST Patent Literature

PTL 1: Japanese Unexamined Patent Application Publication No. 2016-63165

SUMMARY OF THE INVENTION

It is desired, in such a solid-state imaging element and a solid-stateimaging device, for example, to suppress occurrence of transfer failure,etc. of signal charges and to improve element characteristics.

It is therefore desirable to provide a solid-state imaging element and asolid-state imaging device that make it possible to improve elementcharacteristics.

A first solid-state imaging element according to an embodiment of thepresent disclosure includes a photoelectric conversion layer; a firstelectrode and a second electrode opposed to each other with thephotoelectric conversion layer interposed therebetween; a semiconductorlayer provided between the first electrode and the photoelectricconversion layer; an accumulation electrode opposed to the photoelectricconversion layer with the semiconductor layer interposed therebetween;an insulating film provided between the accumulation electrode and thesemiconductor layer; and a barrier layer provided between thesemiconductor layer and the photoelectric conversion layer.

A first solid-state imaging device according to an embodiment of thepresent disclosure includes the first solid-state imaging elementaccording to an embodiment of the present disclosure.

In the first solid-state imaging element and the first solid-stateimaging device according to respective embodiments of the presentdisclosure, signal charges generated in the photoelectric conversionlayer are accumulated in the semiconductor layer, and thereafter areread by the first electrode. Here, the barrier layer is provided betweenthe semiconductor layer and the photoelectric conversion layer, thusmaking the signal charges accumulated in the semiconductor layer lesslikely to return to the photoelectric conversion layer. The barrierlayer functions as a potential or physical barrier during movement ofthe signal charges.

A second solid-state imaging element according to an embodiment of thepresent disclosure includes: a photoelectric conversion layer; a firstelectrode and a second electrode opposed to each other with thephotoelectric conversion layer interposed therebetween; a semiconductorlayer provided between the first electrode and the photoelectricconversion layer and having a potential barrier at ajunction plane withrespect to the photoelectric conversion layer; an accumulation electrodeopposed to the photoelectric conversion layer with the semiconductorlayer interposed therebetween; and an insulating film provided betweenthe accumulation electrode and the semiconductor layer.

A second solid-state imaging device according to an embodiment of thepresent disclosure includes the second solid-state imaging elementaccording to an embodiment of the present disclosure.

In the second solid-state imaging element and the second solid-stateimaging device according to respective embodiments of the presentdisclosure, signal charges generated in the photoelectric conversionlayer are accumulated in the semiconductor layer, and thereafter areread by the first electrode. Here, the potential barrier is provided inthe junction plane between the semiconductor layer and the photoelectricconversion layer, thus making the signal charges accumulated in thesemiconductor layer less likely to return to the photoelectricconversion layer.

According to the first solid-state imaging element and the firstsolid-state imaging device of the respective embodiments of the presentdisclosure, the barrier layer is provided between the semiconductorlayer and the photoelectric conversion layer, and according to thesecond solid-state imaging element and the second solid-state imagingdevice of the respective embodiments of the present disclosure, thepotential barrier is provided at the junction plane between thesemiconductor layer and the photoelectric conversion layer, thus makingit possible to suppress occurrence of transfer failure of signal chargesaccumulated in the semiconductor layer. Accordingly, it is possible toimprove element characteristics.

It is to be noted that, the above content is merely an example of thepresent disclosure. The effects of the present disclosure are notlimited to those described above, and may be other different effects ormay further include other effects.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional schematic view of a schematic configurationof a solid-state imaging element according to a first embodiment of thepresent disclosure.

FIG. 2 is a schematic view of a planar configuration of a firstelectrode and an accumulation electrode illustrated in FIG.

FIG. 3 is a cross-sectional schematic view of another example of asemiconductor layer illustrated in FIG. 1.

FIG. 4A is a diagram (1) that describes energy of a barrier layerillustrated in FIG. 1.

FIG. 4B is a diagram (2) that describes the energy of the barrier layerillustrated in FIG. 1.

FIG. 5 is a cross-sectional schematic view of another example of aphotoelectric conversion layer illustrated in FIG. 1.

FIG. 6 is a cross-sectional schematic view of another example of thesemiconductor layer and the photoelectric conversion layer illustratedin FIG. 1.

FIG. 7 is an equivalent circuit diagram of the solid-state imagingelement illustrated in FIG. 1.

FIG. 8 is a schematic view of arrangement of the first electrode, theaccumulation electrode, and various transistors of the solid-stateimaging element illustrated in FIG. 1.

FIG. 9 is a cross-sectional schematic view of one step in amanufacturing method of the solid-state imaging element illustrated inFIG. 1.

FIG. 10 is a cross-sectional schematic view of a step subsequent to FIG.9.

FIG. 11 is a cross-sectional schematic view of a step subsequent to FIG.10.

FIG. 12 is a cross-sectional schematic view of a step subsequent to FIG.11.

FIG. 13 is a cross-sectional schematic view of a step subsequent to FIG.12.

FIG. 14 is a cross-sectional schematic view of a step subsequent to FIG.13.

FIG. 15 is an explanatory schematic view of an operation of thesolid-state imaging element illustrated in FIG. 1.

FIG. 16 is an explanatory schematic view of global shutter driving ofthe solid-state imaging element illustrated in FIG. 1.

FIG. 17 is a cross-sectional schematic view of a schematic configurationof a solid-state imaging element according to Comparative Example 1.

FIG. 18 is a cross-sectional schematic view of a schematic configurationof a solid-state imaging element according to Comparative Example 2.

FIG. 19 is a cross-sectional schematic view of a schematic configurationof a solid-state imaging element according to Modification Example 1.

FIG. 20 is a cross-sectional schematic view of a schematic configurationof a solid-state imaging element according to Modification Example 2.

FIG. 21 is a cross-sectional schematic view of another example of thesolid-state imaging element illustrated in FIG. 20.

FIG. 22 is a cross-sectional schematic view of a schematic configurationof a solid-state imaging element according to Modification Example 3.

FIG. 23 is a cross-sectional schematic view of another example of thesolid-state imaging element illustrated in FIG. 22.

FIG. 24 is a cross-sectional schematic view of a schematic configurationof a solid-state imaging element according to Modification Example 4.

FIG. 25 is a schematic view of a planar configuration of a firstelectrode, an accumulation electrode, and a transfer electrodeillustrated in FIG. 24.

FIG. 26 is a cross-sectional schematic view of a schematic configurationof a solid-state imaging element according to Modification Example 5.

FIG. 27 is a schematic view of a planar configuration of a firstelectrode, an accumulation electrode and a discharge electrodeillustrated in FIG. 26.

FIG. 28 is a cross-sectional schematic view of a schematic configurationof a solid-state imaging element according to Modification Example 6.

FIG. 29 is a cross-sectional schematic view of a schematic configurationof a solid-state imaging element according to Modification Example 7.

FIG. 30 is a cross-sectional schematic view of a schematic configurationof a solid-state imaging element according to a second embodiment of thepresent disclosure.

FIG. 31 is an explanatory schematic view of a potential barrier formedby a junction plane illustrated in FIG. 30.

FIG. 32 is a block diagram illustrating a configuration of a solid-stateimaging device including the solid-state imaging element illustrated inFIG. 1, etc.

FIG. 33 is a functional block diagram illustrating an example of anelectronic apparatus (camera) using the imaging element illustrated inFIG. 32.

FIG. 34 is a block diagram depicting an example of a schematicconfiguration of an in-vivo information acquisition system.

FIG. 35 is a view depicting an example of a schematic configuration ofan endoscopic surgery system.

FIG. 36 is a block diagram depicting an example of a functionalconfiguration of a camera head and a camera control unit (CCU).

FIG. 37 is a block diagram depicting an example of schematicconfiguration of a vehicle control system.

FIG. 38 is a diagram of assistance in explaining an example ofinstallation positions of an outside-vehicle information detectingsection and an imaging section.

MODES FOR CARRYING OUT THE INVENTION

Hereinafter, description is given in detail of embodiments of thepresent disclosure with reference to the drawings. It is to be notedthat the description is given in the following order.

1. First Embodiment (Example of Solid-State Imaging Element IncludingBarrier Layer between Semiconductor Layer and Photoelectric ConversionLayer)

2. Modification Example 1 (Example of Providing Multilayer Wiring Lineon First Surface of Semiconductor Substrate) 3. Modification Example 2(Example of Including One Photo Diode Section in SemiconductorSubstrate)

4. Modification Example 3 (Example without Photodiode Section inSemiconductor Substrate)

5. Modification Example 4 (Example of Including Transfer ElectrodeBetween First Electrode and Accumulation Electrode)

6. Modification Example 5 (Example of Including Discharge ElectrodeSeparated from First Electrode)7. Modification Example 6 (Example of Including Shielding Electrodebetween Adjacent Accumulation Electrodes)

8. Modification Example 7 (Example of Including Light-Shielding FilmOpposed to First Electrode)

9. Second Embodiment (Solid-State Imaging Element in which PotentialBarrier is Provided at Junction Plane between Semiconductor Layer andPhotoelectric Conversion Layer)

10. Application Example 1 (Example of Solid-State Imaging Device) 11.Applicable Example 2 (Example of Electronic Apparatus) 12. ApplicationExample 3 (Example of Practical Application to In-Vivo InformationAcquisition System) 13. Application Example 4 (Example of PracticalApplication to Endoscopic Surgery System) 14. Application Example 5(Example of Practical Application to Mobile Body) 1. First Embodiment

FIG. 1 schematically illustrates a cross-sectional configuration of asolid-state imaging element (a solid-state imaging element 10) accordingto a first embodiment of the present disclosure. The solid-state imagingelement 10 configures one pixel (a unit pixel P) in a solid-stateimaging device (e.g., a solid-state imaging device 1 in FIG. 32) such asa CMOS image sensor used in an electronic apparatus such as a digitalstill camera or a video camera, for example.

(1-1. Configuration of Solid-State Imaging Element)

The solid-state imaging element 10 is, for example, of a so-calledvertical spectroscopic type in which one organic photoelectricconversion section 20 and two inorganic photoelectric conversionsections 32B and 32R are stacked in a vertical direction. The organicphotoelectric conversion section 20 is provided on side of a firstsurface 30A (back surface) of a semiconductor substrate 30. Thesemiconductor substrate 30 has a second surface 30B (front face) opposedto the first surface 30A. In the solid-state imaging element 10, lightenters from the side of the first surface 30A (light incident side S1),and a multilayer wiring line (wiring layer side S2) is provided on sideof the second surface 30B.

The inorganic photoelectric conversion sections 32B and 32R are eachformed to be embedded in the semiconductor substrate 30, and are stackedin a thickness direction of the semiconductor substrate 30. The organicphotoelectric conversion section 20 includes a photoelectric conversionlayer 25 formed using an organic photoelectric conversion materialbetween a pair of electrodes (a first electrode 21A and a secondelectrode 26) disposed to be opposed to each other. The photoelectricconversion layer 25 includes a p-type semiconductor and an n-typesemiconductor, and has a bulk heterojunction structure in the layer. Thebulk heterojunction structure is a p/n junction plane formed by mixingof the p-type semiconductor and the n-type semiconductor.

The organic photoelectric conversion section 20 and the inorganicphotoelectric conversion sections 32B and 32R each perform photoelectricconversion by selectively detecting light in a different wavelengthregion. Specifically, the organic photoelectric conversion section 20acquires a green (G) color signal. The inorganic photoelectricconversion sections 32B and 32R acquire, respectively, blue (B) and red(R) color signals due to a difference in absorption coefficients. Thisenables the solid-state imaging element 10A to acquire a plurality oftypes of color signals in one pixel without using a color filter.

It is to be noted that, in the present embodiment, description is givenof a case of reading electrons as signal charges among a pair ofelectrons and holes (electron-hole pairs) generated by photoelectricconversion. In addition, in the diagram. “+(plus)” added to “p” and “n”indicates a higher impurity concentration of the p type or the n type,and “++” indicates a still higher impurity concentration of the p typeor the n type than that of “+”.

The second surface 30B of the semiconductor substrate 30 is providedwith, for example, floating diffusions (floating diffusion layers) FD (aregion 36B in the semiconductor substrate 30), FD2 (a region 37C in thesemiconductor substrate 30), FD3 (a region 38C in the semiconductorsubstrate 30), transfer transistors Tr2 and Tr3, an amplifier transistor(modulating element) AMP, a reset transistor RST, a selection transistorSEL, and a multilayer wiring line 40. The multilayer wiring line 40 has,for example, a configuration in which wiring layers 41, 42, and 43 arestacked in an insulating layer 44.

There are provided, between the first surface 30A of the semiconductorsubstrate 30 and the organic photoelectric conversion section 20, forexample, a layer (fixed charge layer) 27 k having a fixed charge, adielectric layer 27 y having an insulating property, and an interlayerinsulating layer 22 s. A protective layer 51 is provided on the organicphotoelectric conversion section 20 (light incident side S1). There areprovided, above the protective layer 51, optical members such as aplanarization layer (not illustrated) and an on-chip lens 52.

A through electrode 34 is provided between the first surface 30A and thesecond surface 30B of the semiconductor substrate 30. The organicphotoelectric conversion section 20 is coupled, via the throughelectrode 34, to a gate Gamp of the amplifier transistor AMP and one ofthe source/drain region 36B, of the reset transistor RST (a resettransistor Tr1rst), which also serves as the floating diffusion FDL.This allows the solid-state imaging element 10 to favorably transfercharges (here, electrons) generated in the organic photoelectricconversion section 20 of the side of the first surface 30A of thesemiconductor substrate 30 to the side of the second surface 30B of thesemiconductor substrate 30 via the through electrode 340, thus making itpossible to enhance the characteristics.

A lower end of the through electrode 340 is coupled to a coupling part41A in the wiring layer 41, and the coupling part 41A and the gate Gampof the amplifier transistor AMP are coupled to each other via a lowerfirst contact 45. The coupling part 41A and the floating diffusion FD1(region 36B) are coupled to each other via, for example, a lower secondcontact 46. An upper end of the through electrode 34 is coupled to thefirst electrode 21A, for example, via a coupling wiring line 39A and anupper first contact 29A.

The through electrode 34 is provided for each organic photoelectricconversion section 20 in each solid-state imaging element 10, forexample. The through electrodes 34 has a function as a connector betweenthe organic photoelectric conversion section 20 and the gate Gamp of theamplifier transistors AMP as well as the floating diffusion FD1, andserves as a transmission path for charges (here, electrons) generated inthe organic photoelectric conversion section 20. The through electrode34 is configured by, for example, a metal material such as aluminum,tungsten, titanium, cobalt, hafnium, and tantalum. The through electrode34 may be configured by a doped silicone material such as PDAS(Phosphorus Doped Amorphous Silicon).

A reset gate Grst of the reset transistor RST is disposed next to thefloating diffusion FD1 (one of the source/drain region 36B of the resettransistor RST). This enables charges accumulated in the floatingdiffusion FD1 to be reset by the reset transistor RST.

In the solid-state imaging element 10 of the present embodiment, lightthat has entered the organic photoelectric conversion section 20 fromside of the second electrode 26 is absorbed by the photoelectricconversion layer 25. Excitons thus generated move to an interfacebetween an electron donor and an electron acceptor that configure thephotoelectric conversion layer 25, and undergo exciton separation, i.e.,dissociate into electrons and holes. One of charges (e.g., electrons)generated here is accumulated in a semiconductor layer 23 opposed to anaccumulation electrode 21B, and the other of charges (e.g., holes) isdischarged to the second electrode 26.

Hereinafter, description is given of a configuration, a material, andthe like of each of the components.

The organic photoelectric conversion section 20 is an organicphotoelectric conversion element that absorbs green light correspondingto a portion or all of a selective wavelength region (e.g., in a rangefrom 450 nm to 650 nm) and generates electron-hole pairs. The organicphotoelectric conversion section 20 includes, in order from a positionclose to the first surface 30A of the semiconductor substrate 30, thefirst electrode 21A and the accumulation electrode 21B, the insulatinglayer 22, the semiconductor layer 23, a barrier layer 24, thephotoelectric conversion layer 25, and the second electrode 26. Theinsulating layer 22 is provided with an opening 22H; the opening 22Hallows the first electrode 21A to be electrically coupled to thesemiconductor layer 23. The insulating layer 22 is interposed betweenthe accumulation electrode 21B and the semiconductor layer 23.

FIG. 2 illustrates a planar configuration of the first electrode 21A andthe accumulation electrode 21B. The first electrode 21A and theaccumulation electrode 21B each have, for example, a quadrangular planarconfiguration, and are disposed apart from each other. For example, anarea of the accumulation electrode 21B is larger than an area of thefirst electrode 21A. One pixel (a pixel P) is provided with, forexample, one first electrode 21A and one accumulation electrode 21B. Thefirst electrode 21A is provided for transferring charges (here,electrons) generated in the photoelectric conversion layer 25 to thefloating diffusion FD1, and functions as a read electrode. The firstelectrode 21A is coupled to the floating diffusion FD1 via, for example,the upper first contact 29A, the coupling wiring line 39A, the throughelectrode 34, the coupling part 41A, and the lower second contact 46.

The accumulation electrode 21B opposed to the photoelectric conversionlayer 25 with the semiconductor layer 23 interposed therebetween isprovided for accumulating, in the semiconductor layer 23, signal charges(e.g., electrons) among the charges generated in the photoelectricconversion layer 25. The accumulation electrode 21B is provided at aregion that is opposed to light receiving surfaces of the inorganicphotoelectric conversion sections 32B and 32R formed in thesemiconductor substrate 30 and covers these light receiving surfaces.The accumulation electrode 21B is electrically coupled to a drivecircuit (not illustrated) via, for example, an upper second contact 29Band a coupling wiring line 39B. Making the area of the accumulationelectrode 21B larger than the area of the first electrode 21A causesmore charges to be accumulated.

The first electrode 21A and the accumulation electrode 21B are eachconfigured by, for example, an electrically-conductive film havinglight-transmissivity, and are configured by, for example, ITO (indiumtin oxide). However, in addition to the ITO, a dopant-doped tin oxide(SnO₂)-based material or a zinc oxide-based material in which aluminumzinc oxide (ZnO) is doped with a dopant may be used as a constituentmaterial of a lower electrode 21. Examples of the zinc oxide-basedmaterial include aluminum zinc oxide (AZO) doped with aluminum (Al) as adopant, gallium (Ga)-doped gallium zinc oxide (GZO), and indium(In)-doped indium zinc oxide (IZO). In addition, aside from thosementioned above, for example, CuI, InSbO₄, ZnMgO, CuInO₂, MgIN₂O₄, CdO,ZnSnO₃, or the like may be used.

The first electrode 21A may be configured by an electrically-conductivematerial having a light-shielding property. Specifically, the firstelectrode 21A may be configured by a film of metal such as aluminum(Al), tungsten (W), titanium (Ti), molybdenum (Mo), tantalum (Ta),copper (Cu), cobalt (Co) or nickel (Ni), or an alloy film thereof, ormay be configured by a film in which silicon or oxygen is contained inthe metal film.

The insulating layer 22 is provided for electrically separating theaccumulation electrode 21B and the semiconductor layer 23 from eachother, and is provided, for example, on an interlayer insulating layer27 s to cover the first electrode 21A and the accumulation electrode21B. The opening 22H provided in the insulating layer 22 causes thefirst electrode 21A to be exposed from the insulating layer 22, and isin contact with the semiconductor layer 23. The insulating layer 22 isconfigured by, for example, a monolayer film of one of silicon oxide,TEOS (Tetra Ethyl Ortho Silicate) silicon nitride, silicon oxynitride(SiON), and the like, or a stacked layer film of two or more of thereof.The insulating layer 22 has a thickness of, for example, 3 nm to 500 nm.

The semiconductor layer 23 provided between the first electrode 21A orthe insulating layer 22 and the photoelectric conversion layer 25 ispreferably configured by a material having higher charge mobility and alarger band gap than those of the photoelectric conversion layer 25. Forexample, the band gap of the constituent material of the semiconductorlayer 23 is preferably 3.0 eV or more. Examples of such a materialinclude an oxide semiconductor material such as IGZO and an organicsemiconductor material. Examples of the organic semiconductor materialinclude transition metal dichalcogenide, silicon carbide, diamond,graphene, a carbon nanotube, a fused polycyclic hydrocarbon compound,and a fused heterocyclic compound. The semiconductor layer 23 may beconfigured by a single film, or may be configured by stacking aplurality of films. The semiconductor layer 23 has a thickness of, forexample, 10 nm to 500 nm preferably 30 nm to 150 nm, and more preferably50 nm to 100 nm. Providing such a semiconductor layer 23 as anunderlayer of the photoelectric conversion layer 25 makes it possible toprevent recombination of charges at the time of charge accumulation andthus to improve transfer efficiency.

An impurity concentration of the constituent material of thesemiconductor layer 23 is preferably 1-10¹⁸ cm⁻³ or less. Thesemiconductor layer 23 is provided in common, for example, for aplurality of solid-state imaging elements 10 (FIG. 1).

As illustrated in FIG. 3, the semiconductor layer 23 may be providedseparately for each of the elements (pixels). At this time, an elementseparation layer (an element separation layer 20 i) is disposed betweenthe semiconductor layers 23 of the adjacent solid-state imaging elements10.

In the present embodiment, the barrier layer 24 is provided between thesemiconductor layer 23 and the photoelectric conversion layer 25. Thebarrier layer 24 functions as a potential or physical barrier duringmovement of signal charges. This makes the signal charges accumulated inthe semiconductor layer 23 less likely to return to the photoelectricconversion layer 25, thus suppressing occurrence of transfer failure,although detailed description thereof is given later. The barrier layer24 controls the movement of charges between the semiconductor layer 23and the photoelectric conversion layer 25, and functions as an energybarrier for the charge movement.

FIG. 4A schematically illustrates electron affinity of constituentmaterials of the barrier layer 24. When the signal charges areelectrons, electron affinity (electron affinity EA2) of the constituentmaterial of the barrier layer 24 is smaller than electron affinity(electron affinity EA1) of the constituent material of the photoelectricconversion layer 25 and electron affinity (electron affinity EA3) of theconstituent material of the semiconductor layer 23. Providing thebarrier layer 24 may cause the electron affinity EA3 of the constituentmaterial of the semiconductor layer 23 to be the same as the electronaffinity EA1 of the constituent material of the photoelectric conversionlayer 25 or to be smaller than the electron affinity EA1. That is, it ispossible to increase a degree of freedom of the constituent materials ofthe semiconductor layer 23 and the photoelectric conversion layer 25.

FIG. 4B schematically illustrates ionization potential of theconstituent material of the barrier layer 24. When the signal chargesare holes, ionization potential (ionization potential IP2) of theconstituent material of the barrier layer 24 is larger than ionizationpotential (ionization potential IP1) of the constituent material of thephotoelectric conversion layer 25 and ionization potential (ionizationpotential IP3) of the constituent material of the semiconductor layer23.

The barrier layer 24 is, for example, configured by silicon oxide (SiO),silicon nitride (SiN) or silicon oxynitride (SiON), and has a thicknessof 0.1 nm to 50 nm, preferably 1 nm to 10 nm. When the signal chargesare electrons, the barrier layer 24 may be configured by an organicmaterial having an electron-injection blocking function. When the signalcharges are holes, the barrier layer 24 may be configured by an organicmaterial having a hole-injection blocking function. The barrier layer 24is provided in common, for example, for the plurality of solid-stateimaging elements 10 (FIG. 1).

The photoelectric conversion laver 25 provided between the barrier layer24 and the second electrode 26 converts optical energy into electricenergy. The photoelectric conversion layer 25 includes, for example, twoor more organic semiconductor materials (p-type semiconductor materialsor n-type semiconductor materials) which function as the p-typesemiconductor or the n-type semiconductor, respectively. Thephotoelectric conversion layer 25 includes, in the layer, a junctionplane (p/n junction plane) between the p-type semiconductor material andthe n-type semiconductor material. The p-type semiconductor functionsrelatively as an electron donor (donor), and the n-type semiconductorfunctions relatively as an electron acceptor (acceptor). Thephotoelectric conversion layer 25 provides a field in which excitonsgenerated upon light absorption separate into electrons and holes;specifically, the excitons separate into electrons and holes at aninterface (p/n junction plane) between the electron donor and theelectron acceptor.

The photoelectric conversion layer 25 may include, in addition to thep-type semiconductor material and the n-type semiconductor material, anorganic semiconductor material, i.e., a so-called dye material thatperforms photoelectric conversion of light in a predetermined wavelengthregion while transmitting light in any other wavelength region. In acase where the photoelectric conversion layer 25 is formed using threetypes of organic semiconductor materials, i.e., the p-type semiconductormaterial, the n-type semiconductor material, and the dye material, thep-type semiconductor material and the n-type semiconductor material areeach preferably a material having light-transmissivity in a visibleregion (e.g., 450 nm to 800 nm). The photoelectric conversion layer 25has a thickness of, for example, 50 nm to 500 nm. The photoelectricconversion layer 25 is provided in common, for example, for theplurality of solid-state imaging elements 10 (FIG. 1).

As illustrated in FIGS. 5 and 6, the photoelectric conversion layer 25may be provided separately for each of the elements (pixels). At thistime, the protective layer 51 is disposed between the photoelectricconversion layers 25 of the adjacent solid-state imaging elements 10.The semiconductor layer 23 may be provided in common for the pluralityof solid-state imaging elements 10, and the barrier layer 24 and thephotoelectric conversion layer 25 may be each provided separately foreach of the elements (FIG. 5). The semiconductor layer 23, the barrierlayer 24, and the photoelectric conversion layer 25 may be each providedseparately for each of the elements (FIG. 6).

The photoelectric conversion layer 25 includes, for example, the p-typesemiconductor, the n-type semiconductor, and the dye material. Examplesof the p-type semiconductor include a thiophene derivative, abenzothienobenzothiophene derivative, a ferrocene derivative, aparaphenylenevinylene derivative, a carbazole derivative, a pyrrolederivative, an aniline derivative, a diamine derivative, aphthalocyanine derivative, a subphthalocyanine derivative, a hydrazonederivative, a naphthalene derivative, an anthracene derivative, aphenanthrene derivative, a pyrene derivative, a perylene derivative, atetracene derivative, a pentacene derivative, a quinacridone derivative,a thienothiophene derivative, a benzothiophene derivative, triarylaminederivative, a perylene derivative, a picene derivative, a chrysenederivative, a fluoranthene derivative, a subporphyrazine derivative, ametal complex including a heterocyclic compound as a ligand, apolythiophene derivative, a polybenzothiadiazole derivative, and apolyfluorene derivative. These materials have relatively high mobility,and thus facilitate design for a hole transport property.

Examples of the n-type semiconductor contained in the photoelectricconversion layer 25 include fullerene or a fullerene derivative. Thefullerene is, for example, high-order fullerene and endohedralfullerene. The high-order fullerene is, for example, C₆₀, C₇₀ and C₇₄,etc. The fullerene derivative is, for example, fullerene fluoride, aPCBM ([6,6]-Phenyl-C61-Butyric Acid Methyl Ester) fullerene compound anda fullerene multimer, etc. The fullerene derivative may include ahalogen atom, an alkyl group, a phenyl group, a functional group havingan aromatic compound, a functional group having a halide, a partialfluoroalkyl group, a perfluoroalkyl group, a silyl alkyl group, a silylalkoxy group, an aryl silyl group, an aryl sulfanyl group, an alkylsulfanyl group, an aryl sulfonyl group, an alkyl sulfonyl group, an arylsulfide group, an alkyl sulfide group, an amino group, an alkyl aminogroup, an aryl amino group, a hydroxy group, an alkoxy group, an acylamino group, an acyloxy group, a carbonyl group, a carboxy group, acarboxyamide group, a carboalkoxy group, an acyl group, a sulfonylgroup, a cyano group, a nitro group, a group having a chalcogenide, aphosphine group, or a phosphone group, etc. The alkyl group may belinear or branched. A cyclic alkyl group may be included in thefullerene derivative. The aromatic compound may include a plurality ofcyclic structures. The plurality of cyclic structures may be bonded by asingle bond or may have a fused ring structure.

The n-type semiconductor included in the photoelectric conversion layer25 may be, for example, an oxazole derivative, an oxadiazole derivative,a triazole derivative, an organic molecule including a heterocycliccompound in a portion of a molecular skeleton, an organic metal complex,or a subphthalocyanine derivative, etc. The heterocyclic compoundcontains a nitrogen atom, an oxygen atom, or a sulfur atom. Examples ofthe heterocyclic compound include a pyridine derivative, a pyrazinederivative, a pyrimidine derivative, a triazine derivative, a quinolinederivative, a quinoxaline derivative, an isoquinoline derivative, anacridine derivative, a phenazine derivative, a phenanthrolinederivative, a tetrazole derivative, a pyrazole derivative, an imidazolederivative, a thiazole derivative, an imidazole derivative, abenzimidazole derivative, a benzotriazole derivative, a benzoxazolederivative, a carbazole derivative, a benzofuran derivative, adibenzofuran derivative, a subporphyrazine derivative, apolyphenylenevinylene derivative, a polybenzothiadiazole derivative, anda polyfluorene derivative, etc. These materials have relatively highmobility, and facilitate design for an electron transport property.

Examples of the dye material contained in the photoelectric conversionlayer 25 include a phthalocyanine derivative, a subphthalocyaninederivative, a quinacridone derivative, a naphthalocyanine derivative,and a squarylium derivative. The photoelectric conversion layer 25 mayinclude a rhodamine-based dye, a merocyanine-based dye, a coumaric aciddye, or a tris-8-hydroxyquinoline aluminum (Alq3), etc. Thephotoelectric conversion layer 25 may include a plurality of materials,or may have a stacked structure. The photoelectric conversion layer 25may include a material that does not directly contribute tophotoelectric conversion.

Another layer may be provided between the photoelectric conversion layer25 and the first electrode 21A (specifically, between the semiconductorlayer 23 and the insulating layer 22) and between the photoelectricconversion layer 25 and the second electrode 26. Specifically, forexample, there may be stacked, in order from side of the first electrode21A, an underlying film, a hole transport layer, an electron blockingfilm, the photoelectric conversion layer 25, a hole blocking film, abuffer film, an electron transport layer, and a work function adjustingfilm, etc.

The second electrode 26 is opposed to the first electrode 21A and theaccumulation electrode 21B, with the semiconductor layer 23, the barrierlayer 24 and the photoelectric conversion layer 25 interposedtherebetween. The second electrode 26 is configured by anelectrically-conductive film having light-transmissivity, similarly tothe first electrode 21A and the accumulation electrode 21B. In thesolid-state imaging device 1 using the solid-state imaging element 10 asone pixel, the second electrodes 26 may be separated for each pixel, ormay be formed as an electrode common to the pixels. The second electrode26 has a thickness of, for example, 10 nm to 200 nm.

The interlayer insulating layer 27 s provided between the insulatinglayer 22 and the first surface 30A of and the semiconductor substrate 30is configured by, for example, a monolayer film of one of silicon oxide,silicon nitride and silicon oxynitride (SiON), or a stacked layer filmof two or more thereof.

The dielectric layer 27 y is provided between the interlayer insulatinglayer 27 s and the first surface 30A of the semiconductor substrate 30.The dielectric layer 27 y is formed by, for example, a silicon oxidefilm, TEOS, a silicon nitride film, a silicon oxynitride film, or thelike, although a material of the dielectric layer 27 y is notparticularly limited.

The fixed charge layer 27 k is provided between the dielectric layer 27y and the first surface 30A of the semiconductor substrate 30. The fixedcharge layer 27 k may be a film having a positive fixed charge, or maybe a film having a negative fixed charge. Examples of the material ofthe film having a negative fixed charge include hafnium oxide, aluminumoxide, zirconium oxide, tantalum oxide, titanium oxide, and the like. Inaddition, as a material other than those mentioned above, there may beused lanthanum oxide, praseodymium oxide, cerium oxide, neodymium oxide,promethium oxide, samarium oxide, europium oxide, gadolinium oxide,terbium oxide, dysprosium oxide, holmium oxide, thulium oxide, ytterbiumoxide, lutetium oxide, yttrium oxide, an aluminum nitride film, ahafnium oxynitride film or an aluminum oxynitride film, etc.

The fixed charge layer 27 k may have a configuration in which two ormore types of films are stacked. Thus, for example, in the case of afilm having negative fixed charges, the function as a hole accumulationlayer is able to be further enhanced.

The protective layer 51 is provided to cover the second electrode 26.The protective layer 51 is configured by a material havinglight-transmissivity, and is configured by, for example, a monolayerfilm of one of silicon oxide, silicon nitride, silicon oxynitride, andthe like, or a stacked layer film of two or more thereof. The protectivelayer 51 has a thickness of, for example, 100 nm to 30000 nm.

An on-chip lens 52 is provided on the protective layer 51. The on-chiplens 52 is provided, for example, at a region opposed to theaccumulation electrode 21B, and condenses incident light to thephotoelectric conversion layer 25 of a part opposed to the accumulationelectrode 21B. The solid-state imaging element 10 may be provided with abonding pad (not illustrated).

The semiconductor substrate 30 is configured by, for example, an n-typesilicon (Si) substrate, and includes a p-well 31 in a predeterminedregion. The second surface 30B of the p-well 31 is provided with theabove-described transfer transistors Tr2 and Tr3, the amplifiertransistor AMP, the reset transistor RST, the selection transistor SEL,and the like. In addition, the peripheral part of the semiconductorsubstrate 30 is provided with a peripheral circuit (not illustrated)including a logic circuit or the like.

FIG. 7 is an equivalent circuit diagram of the solid-state imagingelement 10, and FIG. 8 illustrates arrangement of the transistors,together with the first electrode 21A and the accumulation electrode21B. Description is given of a configuration of the semiconductorsubstrate 30, with reference to FIGS. 7 and 8 together with FIG. 1.

The reset transistor RST (reset transistor TrIrst) resets chargestransferred to the floating diffusion FD1 from the organic photoelectricconversion section 20, and is configured by a MOS transistor, forexample. Specifically, the reset transistor Tr1rst is configured by thereset gate Grst, a channel-forming region 36A, and source/drain regions36B and 36C. The reset gate Grst is coupled to a reset line RST1, andone source/drain region 36B of the reset transistor Tr1rst also servesas the floating diffusion FD1. Another source/drain region 36Cconfiguring the reset transistor Tr1rst is coupled to a power supplyVDD.

The amplifier transistor AMP is a modulation element that modulates anamount of charges generated in the organic photoelectric conversionsection 20 to a voltage, and is configured by a MOS transistor, forexample. Specifically, the amplifier transistor AMP is configured by thegate Gamp, a channel-forming region 35A, and source/drain regions 35Band 35C. The gate Gamp is coupled to the first electrode 21A and the onesource/drain region 36B (floating diffusion FD1) of the reset transistorTr1rst via the lower first contact 45, the coupling part 41A, the lowersecond contact 46 and the through electrode 34, etc. In addition, onesource/drain region 35B shares a region with the other source/drainregion 36C configuring the reset transistor Tr1rst, and is coupled tothe power supply VDD.

The selection transistor SEL (selection transistor TR1sel) is configuredby a gate Gsel, a channel-forming region 34A, and source/drain regions34B and 34C. The gate Gsel is coupled to a selection line SELL. Inaddition, one source/drain region 34B shares a region with anothersource/drain region 35C configuring the amplifier transistor AMP.Another source/drain region 34C is coupled to a signal line (data outputline) VSL1.

The inorganic photoelectric conversion sections 32B and 32R each have ap-n junctionat a predetermined region of the semiconductor substrate 30.The inorganic photoelectric conversion sections 32B and 32R enablespectroscopy of light in the vertical direction by utilizing differentwavelengths of light absorbed in accordance with incident depth of lightin a silicon substrate. The inorganic photoelectric conversion section32B selectively detects blue light to accumulate signal chargescorresponding to a blue color, and is installed at a depth that enablesefficient photoelectric conversion of the blue light. The inorganicphotoelectric conversion section 32R selectively detects red light toaccumulate signal charges corresponding to a red color, and is installedat a depth that enables efficient photoelectric conversion of the redlight. It is to be noted that the blue (B) is a color corresponding to awavelength region of 450 nm to 495 nm, for example, and the red (R) is acolor corresponding to a wavelength region of 620 nm to 750 nm, forexample. It is sufficient for the inorganic photoelectric conversionsections 32B and 32R to be able to detect light in a portion or all ofthe respective wavelength regions.

The inorganic photoelectric conversion section 32B includes, forexample, a p+ region serving as a hole accumulation layer and an nregion serving as an electron accumulation layer. The inorganicphotoelectric conversion section 32R includes, for example, a p+ regionserving as a hole accumulation layer and an n region serving as anelectron accumulation layer (having a p-n-p stacked structure). The nregion of the inorganic photoelectric conversion section 32B is coupledto the vertical transfer transistor Tr2. The p+ region of the inorganicphotoelectric conversion section 32B bends along the transfer transistorTr2, and leads to the p+ region of the inorganic photoelectricconversion section 32R.

The transfer transistor Tr2 (transfer transistor TR2trs) is provided fortransferring, to the floating diffusion FD2, signal charges (here,electrons) corresponding to a blue color, which have been generated andaccumulated in the inorganic photoelectric conversion section 32B. Theinorganic photoelectric conversion section 32B is formed at a deepposition from the second surface 30B of the semiconductor substrate 30,and thus the transfer transistor TR2trs of the inorganic photoelectricconversion section 32B is preferably configured by a verticaltransistor. In addition, the transfer transistor TR2trs is coupled to atransfer gate line TG2. Further, the floating diffusion FD2 is providedin the region 37C in the vicinity of agate Gtrs2 of the transfertransistor TR2trs. The charges accumulated in the inorganicphotoelectric conversion section 32B is read by the floating diffusionFD2 via a transfer channel formed along the gate Gtrs2.

The transfer transistor Tr3 (a transfer transistor TR3trs) transfers, tothe floating diffusion FD3, signal charges (here, electrons)corresponding to the red color generated and accumulated in theinorganic photoelectric conversion section 32R, and is configured by,for example, a MOS transistor. In addition, the transfer transistorTR3trs is coupled to a transfer gate line TG3. Further, the floatingdiffusion FD3 is provided in the region 38C in the vicinity of a gateGtrs3 of the transfer transistor TR3trs. The charges accumulated in theinorganic photoelectric conversion section 32R is read by the floatingdiffusion FD3 via a transfer channel formed along the gate Gtrs3.

There are further provided, on the side of the second surface 30B of thesemiconductor substrate 30, a reset transistor TR2rst, an amplifiertransistor TR2amp, and a selection transistor TR2sel which configure acontroller of the inorganic photoelectric conversion section 32B. Inaddition, there are provided a reset transistor TR3rst, an amplifiertransistor TR3amp, and a selection transistor TR3 se which configure acontroller of the inorganic photoelectric conversion section 32R.

The reset transistor TR2rst is configured by agate, a channel-formingregion, and a source/drain region. A gate of the reset transistor TR2rstis coupled to a reset line RST2, and one of the source/drain region ofthe reset transistor TR2rst is coupled to the power supply VDD. Anotherof the source/drain region of the reset transistor TR2rst also serves asthe floating diffusion FD2.

The amplifier transistor TR2amp is configured by a gate, achannel-forming region, and a source/drain region. The gate is coupledto the other of the source/drain region (floating diffusion FD2) of thereset transistor TR2rst. In addition, one of the source/drain regionconfiguring the amplifier transistor TR2amp shares a region with the oneof the source/drain region configuring the reset transistor TR2rst, andis coupled to the power supply VDD.

The selection transistor TR2sel is configured by a gate, achannel-forming region, and a source/drain region. The gate is coupledto a selection line SEL2. In addition, one of the source/drain regionconfiguring the selection transistor TR2sel shares a region with anotherof the source/drain region configuring the amplifier transistor TR2amp.Another of the source/drain region configuring the selection transistorTR2sel is coupled to a signal line (data output line) VSL2.

The reset transistor TR3rst is configured by a gate, a channel-formingregion, and a source/drain region. A gate of the reset transistor TR3rstis coupled to a reset line RST3, and one of the source/drain regionconfiguring the reset transistor TR3rst is coupled to the power supplyVDD. Another of the source/drain region configuring the reset transistorTR3rst also serves as the floating diffusion FD3.

The amplifier transistor TR3amp is configured by a gate, achannel-forming region, and a source/drain region. The gate is coupledto the other of the source/drain region (floating diffusion FD3)configuring the reset transistor TR3rst. In addition, one of thesource/drain region configuring the amplifier transistor TR3amp shares aregion with the one of the source/drain region configuring the resettransistor TR3rst, and is coupled to the power supply VDD.

The selection transistor TR3sel is configured by a gate, achannel-forming region, and a source/drain region. The gate is coupledto a selection line SEL3. In addition, one of the source/drain regionconfiguring the selection transistor TR3sel shares a region with theother of the of the source/drain region configuring the amplifiertransistor TR3amp. Another of the source/drain region configuring theselection transistor TR3sel is coupled to a signal line (data outputline) VSL3.

The reset lines RST1, RST2, and RST3, the selection lines SEL1, SEL2,and SEL3, and the transfer gate lines TG2 and TG3 are each coupled to avertical drive circuit 112 configuring a drive circuit. The signal lines(data output lines) VSL1, VSL2, and VSL3 are coupled to a column signalprocessing circuit 113 configuring the drive circuit.

The lower first contact 45, the lower second contact 46, the upper firstcontact 29A, and the upper second contact 29B are each configured by adoped silicon material such as PDAS (Phosphorus Doped Amorphous Silicon)or a metal material such as aluminum (Al), tungsten (W), titanium (Ti),cobalt (Co), hafnium (Hf), or tantalum (Ta).

(1-2. Method for Manufacturing Solid-State Imaging Element)

The solid-state imaging element 10 may be manufactured, for example, asfollows (FIGS. 9 to 14).

First, as illustrated in FIG. 9, for example, the p-well 31 is formed asa well of a first electrically-conductive type in the semiconductorsubstrate 30, and the inorganic photoelectric conversion sections 32Band 32R of a second electrically-conductive type (e.g., n-type) areformed in the p-well 31. A p+ region is formed in the vicinity of thefirst surface 30A of the semiconductor substrate 30.

As illustrated in FIG. 9 as well, for example, n+ regions to serve asthe floating diffusions FD1 to FD3 are formed on the second surface 30Bof the semiconductor substrate 30, and thereafter a gate insulatinglayer 33 and a gate wiring layer 47 including respective gates of thetransfer transistor Tr2, the transfer transistor Tr3, the selectiontransistor SEL, the amplifier transistor AMP, and the reset transistorRST are formed. This leads to formation of the transfer transistor Tr2,the transfer transistor Tr3, the selection transistor SEL, the amplifiertransistor AMP, and the reset transistor RST. Further, there are formed,on the second surface 30B of the semiconductor substrate 30, the wiringlayers 41 to 43 (multilayer wiring line 40) including the lower firstcontact 45, the lower second contact 46 and the coupling part 41A, andthe insulating layer 44.

As a base of the semiconductor substrate 30, for example, an SOI(Silicon on Insulator) substrate is used, in which the semiconductorsubstrate 30, a buried oxide film (not illustrated), and a holdingsubstrate (not illustrated) are stacked. Although not illustrated inFIG. 9, the buried oxide film and the holding substrate are joined tothe first surface 30A of the semiconductor substrate 30. After ionimplantation, anneal processing is performed.

Next, a supporting substrate (not illustrated) or another semiconductorsubstrate, etc. is joined to the side of the second surface 30B (side ofmultilayer wiring line 40) of the semiconductor substrate 30, and thesubstrate is vertically inverted. Subsequently, the semiconductorsubstrate 30 is separated from the buried oxide film and the holdingsubstrate of the SOI substrate to expose the first surface 30A of thesemiconductor substrate 30. The above steps may be performed bytechniques used in common CMOS processes, such as ion implantation andCVD (Chemical Vapor Deposition).

Next, as illustrated in FIG. 10, the semiconductor substrate 30 isprocessed from the side of the first surface 30A by dry etching, forexample, to form a ring-shaped opening 34H, for example. As illustratedin FIG. 10, as for the depth, the opening 34H penetrates from the firstsurface 30A to the second surface 30B of the semiconductor substrate 30,and reaches, for example, the coupling part 41A.

Subsequently, for example, the negative fixed charge layer 27 k isformed on the first surface 30A of the semiconductor substrate 30 and aside surface of the opening 34H. Two or more types of films may bestacked as the negative fixed charge layer 27 k. This makes it possibleto further enhance the function as the hole accumulation layer. Afterthe formation of the negative fixed charge layer 27 k, the dielectriclayer 27 y is formed. Next, after formation of the coupling wiring lines39A and 39B at predetermined positions on the dielectric layer 27 y, aphotolithography method and a CMP (Chemical Mechanical Polishing) methodare used to form the interlayer insulating layer 27 s including, forexample, an SiO film, in which the upper first contact 29A and the uppersecond contact 29B are embedded on the coupling wiring lines 39A and39B.

Subsequently, as illustrated in FIG. 11, an electrically-conductive film21 y is formed on the upper first contact 29A, the upper second contact29B and the interlayer insulating layer 27 s, and thereafter aphotoresist PR is formed at a predetermined position of theelectrically-conductive film 21 y. Thereafter, the first electrode 21Aand the accumulation electrode 21B are formed as illustrated in FIG. 12by etching and removal of the photoresist PR.

Then, for example, an SiO film is formed on the interlayer insulatinglayer 27 s, the first electrode 21A and the accumulation electrode 21B,and thereafter a CMP method is used to planarize the SiO film.Subsequently, the insulating layer 22 is formed, as a film, on theinterlayer insulating layer 27 s, the first electrode 21A and theaccumulation electrode 21B. The insulating layer 22 is formed, as afilm, using an ALD (Atomic Layer Deposition) method, for example.

Next, as illustrated in FIG. 13, the photoresist PR is formed on aregion facing the first electrode 21A, and, for example, a dry etchingmethod is used to etch the insulating layer 22. This allows the opening22H to be formed.

Subsequently, as illustrated in FIG. 14, there are formed in order, onthe insulating layer 22 and the first electrode 21A, the semiconductorlayer 23, the barrier layer 24, the photoelectric conversion layer 25,and the second electrode 26. The protective layer 51 is then formed.Thereafter, an optical member such as a planarizing layer and theon-chip lens 52 are disposed. Thus, the solid-state imaging element 10illustrated in FIG. 1 is completed.

(1-3. Operation of Solid-State Imaging Element)

In the solid-state imaging element 10, when light enters the organicphotoelectric conversion section 20 through the on-chip lens 52, thelight passes through the organic photoelectric conversion section 20 andthe inorganic photoelectric conversion sections 32B and 32R in thisorder, and is photoelectrically converted for each light of green, blue,and red in the passage process. Hereinafter, description is given of asignal acquisition operation of each color.

(Acquisition of Green Signal by Organic Photoelectric Conversion Section20)

Green light of the light having entered the solid-state imaging element10 is first selectively detected (absorbed) by the organic photoelectricconversion section 20, and is subjected to photoelectrical conversion.

The organic photoelectric conversion section 20 is coupled to the gateGamp of the amplifier transistor AMP and the floating diffusion FD1 viathe through electrode 34. Therefore, electrons of the electron-holepairs generated in the organic photoelectric conversion section 20 areextracted from side of the first electrode 21A and the accumulationelectrode 21B, transferred to the side of the second surface 30B of thesemiconductor substrate 30 via the through electrode 34, and accumulatedin the floating diffusion FD1. At the same time, a charge amountgenerated in the organic photoelectric conversion section 20 ismodulated into a voltage by the amplifier transistor AMP.

In addition, the reset gate Grst of the reset transistor RST is disposednext to the floating diffusion FD1. Thus, the charges accumulated in thefloating diffusion FD1 are reset by the reset transistor RST.

Here, the organic photoelectric conversion section 20 is coupled notonly to the amplifier transistor AMP but also to the floating diffusionFD1 via the through electrode 34, thus making it possible to easilyreset the charges accumulated in the floating diffusion FD1 by the resettransistor RST.

In contrast, in a case where the through electrode 34 and the floatingdiffusion FD1 are not coupled to each other, it is difficult to resetthe charges accumulated in the floating diffusion FD1, thus resulting inapplication of a large voltage to pull out the charges to the side ofthe second electrode 26. Accordingly, the photoelectric conversion layer25 may be possibly damaged. In addition, the structure that enablesresetting in a short period of time leads to an increase in dark noises,resulting in a trade-off, which structure is thus difficult.

Description is given, with reference to FIG. 15, of accumulation andtransfer of signal charges by the first electrode 21A and theaccumulation electrode 21B.

In the solid-state imaging element 10, changing a potential to beapplied to the accumulation electrode 21B causes charges to beaccumulated and transferred. In the accumulation period, a positivepotential V1 is applied to the accumulation electrode 21B from the drivecircuit. This causes an electric field of a certain amount or more to beapplied to the barrier layer 24, and thus charges (here, electrons)generated in the photoelectric conversion layer 25 move from thephotoelectric conversion layer 25 to the semiconductor layer 23 via thebarrier layer 24, and are accumulated in the semiconductor layer 23 of apart opposed to the accumulation electrode 21B (accumulation period).Holes generated in the photoelectric conversion layer 25 is dischargedvia the second electrode 26.

A reset operation is performed in a later stage of the accumulationperiod. Specifically, a scanning section changes a voltage of the resetsignal RST from a low level to a high level at a predetermined timing.This bring, in the unit pixel P, a reset transistor TR1rst into an onstate; as a result, a voltage of the floating diffusion FD1 is set tothe power supply voltage VDD, and the voltage of the floating diffusionFD1 is reset.

After completion of the reset operation, reading of the signal chargesis performed. Upon the reading of the signal charges, a potential V2 isapplied from the drive circuit to the first electrode 21A. As for thepotential V2, V2<V1 holds true. The potential V2 may be a negativepotential. Here, the barrier layer 24 functions as an insulating layer.The application of the potential V2 to the first electrode 21A causesthe signal charges (here, electrons) accumulated in a part, of thesemiconductor layer 23, opposed to the accumulation electrode 21B to beread by the floating diffusion FD1 via the first electrode 21A. That is,the signal charges accumulated in the semiconductor layer 23 is read bythe controller (transfer period).

In addition, as illustrated in FIG. 16, global shutter driving is alsopossible in the solid-state imaging element 10.

First, in the accumulation period, a predetermined potential V3 isapplied from the drive circuit to the accumulation electrode 21B. Here,the barrier layer 24 functions as an insulating layer, and charges(here, electrons) generated in the photoelectric conversion layer 25 areaccumulated in the photoelectric conversion layer 25 of a part opposedto the accumulation electrode 21B (accumulation period). The holesgenerated in the photoelectric conversion layer 25 are discharged viathe second electrode 26.

In the following transfer period (first transfer period), apredetermined potential V4 is applied from the drive circuit to theaccumulation electrode 21B. As for the potential V4, V3<V4 holds true.This causes an electric field of a certain amount or more to be appliedto the barrier layer 24, and thus signal charges accumulated in thephotoelectric conversion layer 25 are transferred, with all pixels(pixels P) at once, to the semiconductor layer 23 via the barrier layer24 (first transfer period).

The signal charges transferred to the semiconductor layer 23 are heldfor a certain period of time at a part, of the semiconductor layer 23,opposed to the accumulation electrode 21B (memory period). Thereafter,the signal charges are read as needed. Upon reading of the signalcharges, the potential V4 is applied from the drive circuit to the firstelectrode 21A. As for the potential V4, V4<V3 holds true. The potentialV4 may be a negative potential. Here, the barrier layer 24 functions asan insulating layer. The application of the potential V4 to the firstelectrode 21A causes the signal charges (here, electrons) held in thepart, of the semiconductor layer 23, opposed to the accumulationelectrode 21B to be read by the floating diffusion FD1 via the firstelectrode 21A (second transfer period).

(Acquisition of Blue Signal and Red Signal by Inorganic PhotoelectricConversion Sections 32B and 32R)

Of the light transmitted through the organic photoelectric conversionsection 20, blue light and red light are sequentially absorbed by theinorganic photoelectric conversion section 32B and the inorganicphotoelectric conversion section 32R, respectively, and are subjected tophotoelectric conversion. In the inorganic photoelectric conversionsection 32B, electrons corresponding to the incident blue light areaccumulated in an n region of the inorganic photoelectric conversionsection 32B, and the accumulated electrons are transferred to thefloating diffusion FD2 by the transfer transistor Tr2. Similarly, in theinorganic photoelectric conversion section 32R, electrons correspondingto the incident red light are accumulated in an n region of theinorganic photoelectric conversion section 32R, and the accumulatedelectrons are transferred to the floating diffusion FD3 by the transfertransistor Tr3.

(1-3. Workings and Effects)

In the present embodiment, the signal charges generated in thephotoelectric conversion layer 25 are accumulated in the semiconductorlayer 23 of a part opposed to the accumulation electrode 21B. Theaccumulated signal charges are transferred to the first electrode 21Aand are read therefrom. That is, similarly to the inorganicphotoelectric conversion sections 32B and 32R, also in the organicphotoelectric conversion section 20, the signal charges are accumulatedonce and thereafter read by the floating diffusion FD1. This makes itpossible to reset the floating diffusion FD1 immediately before thetransfer of the signal charges. Accordingly, it is possible to remove anoise component and thus to improve quality of a captured image.

In addition, in the present embodiment, the barrier layer 24 is providedbetween the semiconductor layer 23 and the photoelectric conversionlayer 25, thus suppressing occurrence of transfer failure of signalcharges accumulated in the semiconductor layer 23. Hereinafter,description is given thereof with reference to a comparative example(Comparative Example 1).

FIG. 17 illustrates a schematic cross-sectional configuration of a mainpart of a solid-state imaging element (a solid-state imaging element100) according to Comparative Example 1. The solid-state imaging element100 is not provided with a barrier layer (the barrier layer 24 in FIG.1), and the semiconductor layer 23 and the photoelectric conversionlayer 25 are in contact with each other. In such a solid-state imagingelement 100, signal charges accumulated in the semiconductor layer 23 ismore likely to retum to the photoelectric conversion layer 25 havingsmaller mobility. Such backflow of signal charges causes occurrence oftransfer failure of the signal charges.

In contrast, in the present embodiment, the barrier layer 24 is providedbetween the semiconductor layer 23 and the photoelectric conversionlayer 25. The barrier layer 24 functions as an insulating layer when thepotential V2 is applied to the accumulation electrode 21B (FIG. 15),thus suppressing movement of the signal charges straddling the barrierlayer 24 from the semiconductor layer 23. That is, the signal chargesare less likely to return from the semiconductor layer 23 to thephotoelectric conversion layer 25. This suppresses the occurrence oftransfer failure of the signal charges accumulated in the semiconductorlayer 23.

Further, in the present embodiment, the barrier layer 24 is providedbetween the semiconductor layer 23 and the photoelectric conversionlayer 25, thus making it possible to accumulate the signal charges inthe photoelectric conversion layer 25 (accumulation period in FIG. 16)at the time of global shutter driving. The signal charges accumulated inthe photoelectric conversion layer 25 are transferred, with all pixelsat once, to the semiconductor layer 23, and are once held in thesemiconductor layer 23 (memory period in FIG. 16). In this manner, theaccumulation, transfer and holding (memory) of the signal charges areperformed along the stacking direction of the semiconductor layer 23,the barrier layer 24 and the photoelectric conversion layer 25, thusmaking it possible to achieve global shutter driving without reducing anumerical aperture. Hereinafter, description is given thereof withreference to a comparative example (Comparative Example 2).

FIG. 18 illustrates a schematic cross-sectional configuration of a mainpart of a solid-state imaging element (a solid-state imaging element101) according to Comparative Example 2. Similar to the solid-stateimaging element 100, the solid-state imaging element 101 is not providedwith a barrier layer (the barrier layer 24 in FIG. 1). The solid-stateimaging element 101 includes a memory electrode (a memory electrode21M), and is configured to enable global shutter driving. For example,the memory electrode 21M is provided side by side between the firstelectrode 21A and the accumulation electrode 21B. The semiconductorlayer 23 of apart opposed to the first electrode 21A and memoryelectrode 21M is covered with a light-shielding film (a light-shieldingfilm 54).

In the solid-state imaging element 101, signal charges generated in thephotoelectric conversion layer 25 moves to the semiconductor layer 23,and is accumulated in a part, of the semiconductor layer 23, opposed tothe accumulation electrode 21B. Thereafter, the signal charges aretransferred, with all pixels at once, inside the semiconductor layer 23,from the part opposed to the accumulation electrode 21B to a partopposed to the memory electrode 21M, and are held. That is, theaccumulation, transfer and holding (memory) of the signal charges areperformed along a planar direction of the semiconductor layer 23, thusshielding the semiconductor layer 23 of the part opposed to the memoryelectrode 21M from light. Accordingly, the numerical aperture is reduceddue to the provision of the global shutter function.

In contrast, in the present embodiment, as described above, theaccumulation, transfer and holding (memory) of the signal charges areperformed along the stacking direction of the semiconductor layer 23,the barrier layer 24 and the photoelectric conversion layer 25, thusmaking it possible to achieve the global shutter driving withoutreducing the numerical aperture.

As described above, in the solid-state imaging element 10 according tothe present embodiment, the barrier layer 24 is provided between thesemiconductor layer 23 and the photoelectric conversion layer 25, thusmaking it possible to suppress the occurrence of the transfer failure ofthe signal charges accumulated in the semiconductor layer 23. Therefore,it becomes possible to improve element characteristics.

In addition, in the present embodiment, the provision of the barrierlayer 24 allows the accumulation, transfer and holding (memory) of thesignal charges to be performed along the stacking direction of thesemiconductor layer 23, the barrier layer 24, and the photoelectricconversion layer 25, thus making it possible to achieve the globalshutter driving without reducing the numerical aperture.

Hereinafter, description is given of modification examples of the firstembodiment and another embodiment; components similar to those of thefirst embodiment are denoted with the same reference numerals, anddescriptions thereof are omitted as appropriate.

2. Modification Example 1

FIG. 19 schematically illustrates a cross-sectional configuration of amain part of a solid-state imaging element (a solid-state imagingelement 10A) according to Modification Example 1 of the foregoing firstembodiment. The solid-state imaging element 10A is a front-illuminatedsolid-state imaging element; light enters the semiconductor substrate 30from the side of the second surface 30B. Except for this point, thesolid-state imaging element 10A has configurations and effects similarto those of the solid-state imaging element 10.

The coupling part 41A, the multilayer wiring line 40, and the interlayerinsulating layer 27 s, etc. are provided between the second surface 30Bof the semiconductor substrate 30 and the organic photoelectricconversion section 20 (first electrode 21A and accumulation electrode21B). The first electrode 21A is coupled to the coupling part 41A viathe upper first contact 29A and the coupling wiring line 39A provided inthe interlayer insulating layer 27 s. That is, the front-illuminatedsolid-state imaging element 10A eliminates the need of the throughelectrode (through electrode 34 in FIG. 1) of the semiconductorsubstrate 30.

3. Modification Example 2

FIG. 20 schematically illustrates a cross-sectional configuration of amain part of a solid-state imaging element (a solid-state imagingelement 10B) according to Modification Example 2 of the foregoing firstembodiment. The solid-state imaging element 10B has one inorganicphotoelectric conversion section (an inorganic photoelectric conversionsection 32C) in the semiconductor substrate 30. Except for this point,the solid-state imaging element 10B has configurations and effectssimilar to those of the solid-state imaging element 10.

The inorganic photoelectric conversion section 32C is a part thatperforms photoelectric conversion of the light transmitted through acolor filter layer 53 and the organic photoelectric conversion section20. The solid-state imaging element 10B may be provided with theinorganic photoelectric conversion section 32C that detects light beamsof different colors. The solid-state imaging element 10B includes, forexample, the color filter layer 53 between the organic photoelectricconversion section 20 and the on-chip lens 52, and the color filterlayer 53 is disposed at a position opposed to the inorganicphotoelectric conversion section 32C. The color filter layer 53 may beprovided between the semiconductor substrate 30 and the organicphotoelectric conversion section 20 (not illustrated).

In this manner, there may be one inorganic photoelectric conversionsection (inorganic photoelectric conversion section 32C) provided in thesemiconductor substrate 30. It is possible, in the solid-state imagingelement 10B, to selectively utilize light of any wavelength for eachpixel.

As illustrated in FIG. 21, the solid-state imaging element 10B may be afront-illuminated solid-state imaging element.

4. Modification Example 3

FIG. 22 schematically illustrates a cross-sectional configuration of amain part of a solid-state imaging element (a solid-state imagingelement 10C) according to Modification Example 3 of the foregoing firstembodiment. In the solid-state imaging element 10C, no inorganicphotoelectric conversion section (inorganic photoelectric conversionsections 32R and 32B in FIG. 1 or inorganic photoelectric conversionsection 32C in FIG. 20) is provided in the semiconductor substrate 30.Except for this point, the solid-state imaging element 10C hasconfigurations and effects similar to those of the solid-state imagingelement 10.

The solid-state imaging element 10C has the color filter layer 53,similarly to the foregoing solid-state imaging element 10B ofModification Example 2. The color filter layer 53 may be providedbetween the organic photoelectric conversion section 20 and the on-chiplens 52 (FIG. 20), or may be provided between the semiconductorsubstrate 30 and the organic photoelectric conversion section 20 (notillustrated). It is possible, in such a solid-state imaging element 10C,to selectively utilize light of any wavelength for each pixel.

In addition, no inorganic photoelectric conversion section is providedin the semiconductor substrate 30, thus making it possible to improve adegree of freedom of selection of electrically-conductive materialsconfiguring the first electrode 21A and the accumulation electrode 21B.Specifically, the electrically-conductive materials configuring thefirst electrode 21A and the accumulation electrode 21B are not limitedto light-transmissive electrically-conductive materials; more versatilemetal materials may be used.

Further, in the solid-state imaging element 10C of a back-illuminatedtype, use of the semiconductor substrate 30 allows for configuration ofa stacked-type imaging element.

As illustrated in FIG. 23, the solid-state imaging element 10C may be afront-illuminated solid-state imaging element. In the solid-stateimaging element 10C, a circuit for improving functions may be providedin the semiconductor substrate 30 of a part opposed to the firstelectrode 21A and the accumulation electrode 21B.

5. Modification Example 4

FIG. 24 schematically illustrates a cross-sectional configuration of amain part of a solid-state imaging element (a solid-state imagingelement 10D) according to Modification Example 4 of the foregoing firstembodiment. The solid-state imaging element 10D includes, in addition tothe first electrode 21A and the accumulation electrode 21B, a transferelectrode 21C as an electrode opposed to the second electrode 26 withthe semiconductor layer 23 interposed therebetween. The transferelectrode 21C is provided for controlling the movement of signal chargesin the semiconductor layer 23. Except for this point, the solid-stateimaging element 10D has configurations and effects similar to those ofthe solid-state imaging element 10.

FIG. 25 illustrates a planar configuration of the first electrode 21A,the accumulation electrode 21B, and the transfer electrode 21C. Thefirst electrode 21A, the accumulation electrode 21B, and the transferelectrode 21C are provided apart from each other. The transfer electrode21C has, for example, a quadrangular planar shape, and is provided sideby side with the first electrode 21A and the accumulation electrode 21B.The transfer electrode 21C is arranged between the first electrode 21Aand the accumulation electrode 21B.

The transfer electrode 62C is provided for improving efficiency oftransferring signal charges accumulated in the accumulation electrode21B to the first electrode 21A, and is opposed to the semiconductorlayer 23 with the insulating layer 22 interposed therebetween. Thetransfer electrode 21C is coupled, for example, to a pixel drive circuit(not illustrated) configuring the drive circuit via an upper thirdcontact 29C and a coupling wiring line 39C. The first electrode 21A, theaccumulation electrode 21B, and the transfer electrode 21C are able toapply a voltage independently of one another. For example, adjusting apotential applied to the transfer electrode 21C makes it possible toprevent signal charges accumulated in the semiconductor layer 23 of apart opposed to the accumulation electrode 21B from unintentionallymoving to the first electrode 21A.

In this manner, in the solid-state imaging element 10D, the transferelectrode 21C between the first electrode 21A and the accumulationelectrode 21B is able to further improve the transfer efficiency of thesignal charges accumulated in the semiconductor layer 23.

The solid-state imaging element 10D may be of a front-illuminated type(see FIG. 19). One inorganic photoelectric conversion section 32C may beprovided in the semiconductor substrate 30 of the solid-state imagingelement 10D (see FIGS. 20 and 21), or no inorganic photoelectricconversion section may be provided in the semiconductor substrate 30(see FIGS. 22 and 23).

6. Modification Example 5

FIG. 26 schematically illustrates a cross-sectional configuration of amain part of a solid-state imaging element (a solid-state imagingelement 10E) according to Modification Example 5 of the foregoing firstembodiment. The solid-state imaging element 10E includes, in addition tothe first electrode 21A and the accumulation electrode 21B, a dischargeelectrode 21D as an electrode opposed to the second electrode 26 withthe semiconductor layer 23 interposed therebetween. Except for thispoint, the solid-state imaging element 10E has configurations andeffects similar to those of the solid-state imaging element 10.

FIG. 27 illustrates a planar configuration of the first electrode 21A,the accumulation electrode 21B, and the discharge electrode 21D. Thefirst electrode 21A, the accumulation electrode 21B, and the dischargeelectrode 21D are provided apart from each other. The dischargeelectrode 21D is provided to surround the first electrode 21A and theaccumulation electrode 21B, for example. The discharge electrode 21D isprovided in common for the pixel, for example. The discharge electrode21D may be provided separately for each pixel (not illustrated).

The discharge electrode 21D is provided at an opening of the insulatinglayer 22, and is electrically coupled to the semiconductor layer 23. Thedischarge electrode 21D is provided for sending, to the drive circuit,signal charges not sufficiently attracted by the accumulation electrode21B or excess signal charges (so-called overflowed signal charges) upongeneration of signal charges more than transfer capability. Thedischarge electrode 21D is coupled, for example, to a pixel drivecircuit (not illustrated) configuring the drive circuit via an upperfourth contact 29D and a coupling wiring line 39D. The first electrode21A, the accumulation electrode 21B, and the discharge electrode 21D areable to apply a voltage independently of one another.

In this manner, in the solid-state imaging element 10E, the dischargeelectrode 21D electrically coupled to the semiconductor layer 23 enablesthe excess signal charges generated in the semiconductor layer 23 to bedischarged without remaining in the semiconductor layer 23.

The solid-state imaging element 10E may be of a front-illuminated type(see FIG. 19). One inorganic photoelectric conversion section 32C may beprovided in the semiconductor substrate 30 of the solid-state imagingelement 10E, (see FIGS. 20 and 21), or no inorganic photoelectricconversion section may be provided in the semiconductor substrate 30(see FIGS. 22 and 23). The solid-state imaging element 10E may includethe transfer electrode 21C together with the discharge electrode 21D(see FIG. 24).

7. Modification Example 6

FIG. 28 schematically illustrates a cross-sectional configuration of amain part of a solid-state imaging element (a solid-state imagingelement 10F) according to Modification Example 6 of the foregoing firstembodiment. The solid-state imaging element 10F includes, in addition tothe first electrode 21A and the accumulation electrode 21B, a shieldingelectrode 21E as an electrode opposed to the second electrode 26 withthe semiconductor layer 23 interposed therebetween. Except for thispoint, the solid-state imaging element 10F has configurations andeffects similar to those of the solid-state imaging element 10.

The first electrode 21A, the accumulation electrode 21B, and theshielding electrode 21E are provided apart from each other. Theshielding electrode 21E is provided side by side with the firstelectrode 21A and the accumulation electrode 21B, and is arrangedbetween the accumulation electrodes 21B adjacent to each other. Theshielding electrode 21E is provided for suppressing leakage (leak) ofsignal charges between the adjacent accumulation electrodes 21B, and isopposed to the semiconductor layer 23 with the insulating layer 22interposed therebetween. The shielding electrode 21E is coupled, forexample, to a pixel drive circuit (not illustrated) configuring thedrive circuit via an upper fifth contact 29E and a coupling wiring line39E. The first electrode 21A, the accumulation electrode 21B, and theshielding electrode 21E are able to apply a voltage independently of oneanother.

In this manner, in the solid-state imaging element 10F, the shieldingelectrode 21E provided between the adjacent accumulation electrodes 21Bis able to suppress the leakage of the signal charges between theadjacent accumulation electrodes 21B.

The solid-state imaging element 10F may be of a front-illuminated type(see FIG. 19). One inorganic photoelectric conversion section 32C may beprovided in the semiconductor substrate 30 of the solid-state imagingelement 10F (see FIGS. 20 and 21), or no inorganic photoelectricconversion section may be provided in the semiconductor substrate 30(see FIGS. 22 and 23). The solid-state imaging element 10F may includethe transfer electrode 21C (see FIG. 24) or the discharge electrode 21D(see FIG. 26) together with the shielding electrode 21E.

8. Modification Example 7

FIG. 29 schematically illustrates a cross-sectional configuration of amain part of a solid-state imaging element (a solid-state imagingelement 10G) according to Modification Example 7 of the foregoing firstembodiment. The solid-state imaging element 10G includes thelight-shielding film 54 that covers the first electrode 21A with thephotoelectric conversion layer 25 interposed therebetween. Except forthis point, the solid-state imaging element 10G has configurations andeffects similar to those of the solid-state imaging element 10.

The light-shielding film 54 is provided, for example, between the secondelectrode 26 and the on-chip lens 52, and covers the photoelectricconversion layer 25 of a part opposed to the first electrode 21A. Thisallows for suppression of photoelectric conversion at a region(photoelectric conversion layer 25) close to the first electrode 21A.Accordingly, it is possible to suppress transfer of excess signalcharges to the first electrode 21A. The light-shielding film 54contains, for example, metal such as tungsten (W) and aluminum (Al), andmay be configured by a single metal or may be configured by an alloy.The light-shielding film 54 may include the constituent material of thecolor filter layer (e.g., color filter layer 53 in FIG. 20), and mayhave a stacked structure. A portion of the accumulation electrode 21Bmay be covered with the light-shielding film 54.

In this manner, in the solid-state imaging element 10G, thephotoelectric conversion layer 25 of a part opposed to the firstelectrode 21A is covered with the light-shielding film 54, thussuppressing the transfer of excess signal charges to the first electrode21A.

The solid-state imaging element 10G may be of a front-illuminated type(see FIG. 19). One inorganic photoelectric conversion section 32C may beprovided in the semiconductor substrate 30 of the solid-state imagingelement 10G (see FIGS. 20 and 21), or no inorganic photoelectricconversion section may be provided in the semiconductor substrate 30(see FIGS. 22 and 23). The solid-state imaging element 10G may includethe transfer electrode 21C (see FIG. 24), the discharge electrode 21D(see FIG. 26), or the shielding electrode 21E (see FIG. 28). A portionof the transfer electrode 21C, the discharge electrode 21D, or theshielding electrode 21E may be covered with the light-shielding film 54.

9. Second Embodiment

FIG. 30 schematically illustrates a cross-sectional configuration of amain part of a solid-state imaging element (a solid-state imagingelement 60) of a second embodiment of the present disclosure. In thesolid-state imaging element 60, a junction plane (a junction plane 20S)between the semiconductor layer 23 and the photoelectric conversionlayer 25 functions as a potential barrier. That is, the solid-stateimaging element 60 is provided with the junction plane 20S serving as apotential barrier, instead of the barrier layer (barrier layer 24 inFIG. 1). Except for this point, the solid-state imaging element 60 hasconfigurations and effects similar to those of the solid-state imagingelement 10 of the foregoing first embodiment.

FIG. 31 illustrates an example of potential energy of the semiconductorlayer 23 and the photoelectric conversion layer 25. In this manner, apotential barrier is formed at the junction plane 20S between thesemiconductor layer 23 and the photoelectric conversion layer 25. Forexample, such a junction plane 20S is configured under the followingconditions.

When the signal charges are electrons, the semiconductor layer 23 haspotential energy in a conduction band lower than a potential of aconductor of the photoelectric conversion layer 25, and has a Fermilevel (vacuum level reference) lower than a Fermi level of thephotoelectric conversion layer 25. When the signal charges are holes,the semiconductor layer 23 has potential energy higher than potentialenergy of a valence band of the photoelectric conversion layer 25, andhas a Fermi level lower than a Fermi level of the photoelectricconversion layer 25.

In this manner, in the solid-state imaging element 60, the junctionplane 20S between the semiconductor layer 23 and the photoelectricconversion layer 25 functions as a potential barrier, thus making itpossible to suppress the occurrence of transfer failure of signalcharges accumulated in the semiconductor layer 23, similarly to theabove-described solid-state imaging element 10. Accordingly, it becomespossible to improve the element characteristics.

In addition, the junction plane 20S allows the accumulation, transferand holding (memory) of the signal charges to be performed along thestacking direction of the semiconductor layer 23 and the photoelectricconversion layer 25, thus making it possible to achieve the globalshutter driving without reducing the numerical aperture.

The solid-state imaging element 60 may be of a front-illuminated type(see FIG. 19). One inorganic photoelectric conversion section 32C may beprovided in the semiconductor substrate 30 of the solid-state imagingelement 60 (see FIGS. 20 and 21), or no inorganic photoelectricconversion section may be provided in the semiconductor substrate 30(see FIGS. 22 and 23). The solid-state imaging element 60 may includethe transfer electrode 21C (see FIG. 24), the discharge electrode 21D(see FIG. 26), or the shielding electrode 21E (see FIG. 28). Thesolid-state imaging element 60 may be provided with the light-shieldingfilm 54 (see FIG. 29).

Application Example 1

FIG. 32 illustrates an overall configuration of the solid-state imagingdevice (solid-state imaging device 1) in which the solid-state imagingelement 10 (or solid-state imaging elements 10A to 10G and 60;hereinafter, collectively referred to as the solid-state imaging element10) described in the foregoing embodiment, etc. is used for each pixel.The solid-state imaging device 1 is a CMOS image sensor, and includes apixel section 1 a as an imaging area on the semiconductor substrate 30,and includes, for example, a peripheral circuit section 130 configuredby a row scanning section 131, a horizontal selection section 133, acolumn scanning section 134, and a system control section 132 in aperipheral region of the pixel section 1 a.

The pixel section 1 a includes, for example, a plurality of pixels P(solid-state imaging elements 10) arranged two-dimensionally in matrix.To the pixel P, for example, pixel drive lines Lread (e.g., rowselection lines and reset control lines) are wired on a pixel-row basis,and vertical signal lines Lsig are wired on a pixel-column basis. Thepixel drive line Lread transmits a drive signal for reading of a signalfrom the pixel P. One end of the pixel drive line Lread is coupled to anoutput terminal corresponding to each row in the row scanning section131.

The row scanning section 131 is configured by a shift register, anaddresses decoder, and the like, and is, for example, a pixel drivesection that drives the respective pixels P of an element region R1 on arow-unit basis. Signals outputted from the respective pixels P in thepixel row selectively scanned by the row scanning section 131 aresupplied to the horizontal selection section 133 via the respectivevertical signal lines Lsig. The horizontal selection section 133 isconfigured by an amplifier, a horizontal selection switch, and the likethat are provided for each of the vertical signal lines Lsig.

The column scanning section 134 is configured by a shift register, anaddress decoder, and the like, and sequentially drives respectivehorizontal selection switches in the horizontal selection section 133while scanning. As a result of the selective scanning by the columnscanning section 134, signals of respective pixels to be transmitted viathe respective vertical signal lines Lsigs are outputted sequentially toa horizontal signal line 135, and are inputted to an unillustratedsignal processing section or the like through the horizontal signal line135.

The system control section 132 receives a clock supplied from theoutside, data instructing an operation mode, or the like, and outputsdata such as internal information of an imaging element 4. The systemcontrol section 132 further includes a timing generator that generatesvarious timing signals, and performs drive control of the row scanningsection 131, the horizontal selection section 133, and the columnscanning section 134 on the basis of various timing signals generated bythe timing generator.

Application Example 2

The above-described solid-state imaging device 1 is applicable to anytype of electronic apparatus having an imaging function, for example, acamera system such as a digital still camera or a video camera, or amobile phone having an imaging function. FIG. 33 illustrates a schematicconfiguration of an electronic apparatus 2 (camera) as an examplethereof. The electronic apparatus 2 is, for example, a video camera thatis able to capture a still image or shoot a moving image, and includesthe solid-state imaging device 1, an optical system (optical lens) 310,a shutter device 311, a drive section 313 that drives the solid-stateimaging device 1 and the shutter device 311, and a signal processingsection 312.

The optical system 310 guides image light (incident light) from asubject to the imaging element 4. The optical system 310 may beconfigured by a plurality of optical lenses. The shutter device 311controls periods of light irradiation and light shielding with respectto the solid-state imaging device 1. The drive section 313 controls atransfer operation of the solid-state imaging device 1 and a shutteroperation of the shutter device 311. The signal processing section 312performs various types of signal processing on a signal outputted fromthe solid-state imaging device 1. An image signal Dout after the signalprocessing is stored in a storage medium such as a memory or outputtedto a monitor or the like.

Application Example 3 <Example of Practical Application to In-VivoInformation Acquisition System>

Further, the technology according to an embodiment of the presentdisclosure (present technology) is applicable to various products. Forexample, the technology according to an embodiment of the presentdisclosure may be applied to an endoscopic surgery system.

FIG. 34 is a block diagram depicting an example of a schematicconfiguration of an in-vivo information acquisition system of a patientusing a capsule type endoscope, to which the technology according to anembodiment of the present disclosure (present technology) can beapplied.

The in-vivo information acquisition system 10001 includes a capsule typeendoscope 10100 and an external controlling apparatus 10200.

The capsule type endoscope 10100 is swallowed by a patient at the timeof inspection. The capsule type endoscope 10100 has an image pickupfunction and a wireless communication function and successively picks upan image of the inside of an organ such as the stomach or an intestine(hereinafter referred to as in-vivo image) at predetermined intervalswhile it moves inside of the organ by peristaltic motion for a period oftime until it is naturally discharged from the patient. Then, thecapsule type endoscope 10100 successively transmits information of thein-vivo image to the external controlling apparatus 10200 outside thebody by wireless transmission.

The external controlling apparatus 10200 integrally controls operationof the in-vivo information acquisition system 10001. Further, theextemal controlling apparatus 10200 receives information of an in-vivoimage transmitted thereto from the capsule type endoscope 10100 andgenerates image data for displaying the in-vivo image on a displayapparatus (not depicted) on the basis of the received information of thein-vivo image.

In the in-vivo information acquisition system 10001, an in-vivo imageimaged a state of the inside of the body of a patient can be acquired atany time in this manner for a period of time until the capsule typeendoscope 10100 is discharged after it is swallowed.

A configuration and functions of the capsule type endoscope 10100 andthe external controlling apparatus 10200 are described in more detailbelow.

The capsule type endoscope 10100 includes a housing 10101 of the capsuletype, in which a light source unit 10111, an image pickup unit 10112, animage processing unit 10113, a wireless communication unit 10114, apower feeding unit 10115, a power supply unit 10116 and a control unit10117 are accommodated.

The light source unit 10111 includes a light source such as, forexample, a light emitting diode (LED) and irradiates light on an imagepickup field-of-view of the image pickup unit 10112.

The image pickup unit 10112 includes an image pickup element and anoptical system including a plurality of lenses provided at a precedingstage to the image pickup element. Reflected light (hereinafter referredto as observation light) of light irradiated on a body tissue which isan observation target is condensed by the optical system and introducedinto the image pickup element. In the image pickup unit 10112, theincident observation light is photoelectrically converted by the imagepickup element, by which an image signal corresponding to theobservation light is generated. The image signal generated by the imagepickup unit 10112 is provided to the image processing unit 10113.

The image processing unit 10113 includes a processor such as a centralprocessing unit (CPU) or a graphics processing unit (GPU) and performsvarious signal processes for an image signal generated by the imagepickup unit 10112. The image processing unit 10113 provides the imagesignal for which the signal processes have been performed thereby as RAWdata to the wireless communication unit 10114.

The wireless communication unit 10114 performs a predetermined processsuch as a modulation process for the image signal for which the signalprocesses have been performed by the image processing unit 10113 andtransmits the resulting image signal to the external controllingapparatus 10200 through an antenna 10114A. Further, the wirelesscommunication unit 10114 receives a control signal relating to drivingcontrol of the capsule type endoscope 10100 from the externalcontrolling apparatus 10200 through the antenna 10114A. The wirelesscommunication unit 10114 provides the control signal received from theexternal controlling apparatus 10200 to the control unit 10117.

The power feeding unit 10115 includes an antenna coil for powerreception, a power regeneration circuit for regenerating electric powerfrom current generated in the antenna coil, a voltage booster circuitand so forth. The power feeding unit 10115 generates electric powerusing the principle of non-contact charging.

The power supply unit 10116 includes a secondary battery and storeselectric power generated by the power feeding unit 10115. In FIG. 34, inorder to avoid complicated illustration, an arrow mark indicative of asupply destination of electric power from the power supply unit 10116and so forth are omitted. However, electric power stored in the powersupply unit 10116 is supplied to and can be used to drive the lightsource unit 10111, the image pickup unit 10112, the image processingunit 10113, the wireless communication unit 10114 and the control unit10117.

The control unit 10117 includes a processor such as a CPU and suitablycontrols driving of the light source unit 10111, the image pickup unit10112, the image processing unit 10113, the wireless communication unit10114 and the power feeding unit 10115 in accordance with a controlsignal transmitted thereto from the external controlling apparatus10200.

The external controlling apparatus 10200 includes a processor such as aCPU or a GPU, a microcomputer, a control board or the like in which aprocessor and a storage element such as a memory are mixedlyincorporated. The external controlling apparatus 10200 transmits acontrol signal to the control unit 10117 of the capsule type endoscope10100 through an antenna 10200A to control operation of the capsule typeendoscope 10100. In the capsule type endoscope 10100, an irradiationcondition of light upon an observation target of the light source unit10111 can be changed, for example, in accordance with a control signalfrom the extemal controlling apparatus 10200. Further, an image pickupcondition (for example, a frame rate, an exposure value or the like ofthe image pickup unit 10112) can be changed in accordance with a controlsignal from the external controlling apparatus 10200. Further, thesubstance of processing by the image processing unit 10113 or acondition for transmitting an image signal from the wirelesscommunication unit 10114 (for example, a transmission interval, atransmission image number or the like) may be changed in accordance witha control signal from the external controlling apparatus 10200.

Further, the external controlling apparatus 10200 performs various imageprocesses for an image signal transmitted thereto from the capsule typeendoscope 10100 to generate image data for displaying a picked upin-vivo image on the display apparatus. As the image processes, varioussignal processes can be performed such as, for example, a developmentprocess (demosaic process), an image quality improving process(bandwidth enhancement process, a super-resolution process, a noisereduction (NR) process and/or image stabilization process) and/or anenlargement process (electronic zooming process). The externalcontrolling apparatus 10200 controls driving of the display apparatus tocause the display apparatus to display a picked up in-vivo image on thebasis of generated image data. Alternatively, the external controllingapparatus 10200 may also control a recording apparatus (not depicted) torecord generated image data or control a printing apparatus (notdepicted) to output generated image data by printing.

The description has been given above of one example of the in-vivoinformation acquisition system, to which the technology according to anembodiment of the present disclosure is applicable. The technologyaccording to an embodiment of the present disclosure is applicable to,for example, the image pickup unit 10112 of the configurations describedabove. This makes it possible to improve detection accuracy.

Application Example 4 <Example of Practical Application to EndoscopicSurgery System>

The technology according to an embodiment of the present disclosure(present technology) is applicable to various products. For example, thetechnology according to an embodiment of the present disclosure may beapplied to an endoscopic surgery system.

FIG. 35 is a view depicting an example of a schematic configuration ofan endoscopic surgery system to which the technology according to anembodiment of the present disclosure (present technology) can beapplied.

In FIG. 35, a state is illustrated in which a surgeon (medical doctor)11131 is using an endoscopic surgery system 11000 to perform surgery fora patient 11132 on a patient bed 11133. As depicted, the endoscopicsurgery system 11000 includes an endoscope 11100, other surgical tools11110 such as a pneumoperitoneum tube 11111 and an energy device 11112,a supporting arm apparatus 11120 which supports the endoscope 11100thereon, and a cart 11200 on which various apparatus for endoscopicsurgery are mounted.

The endoscope 11100 includes a lens barrel 11101 having a region of apredetermined length from a distal end thereof to be inserted into abody cavity of the patient 11132, and a camera head 11102 connected to aproximal end of the lens barrel 11101. In the example depicted, theendoscope 11100 is depicted which includes as a rigid endoscope havingthe lens barrel 11101 of the hard type. However, the endoscope 11100 mayotherwise be included as a flexible endoscope having the lens barrel11101 of the flexible type.

The lens barrel 11101 has, at a distal end thereof, an opening in whichan objective lens is fitted. A light source apparatus 11203 is connectedto the endoscope 11100 such that light generated by the light sourceapparatus 11203 is introduced to a distal end of the lens barrel 11101by a light guide extending in the inside of the lens barrel 11101 and isirradiated toward an observation target in a body cavity of the patient11132 through the objective lens. It is to be noted that the endoscope11100 may be a forward-viewing endoscope or may be an oblique-viewingendoscope or a side-viewing endoscope.

An optical system and an image pickup element are provided in the insideof the camera head 11102 such that reflected light (observation light)from the observation target is condensed on the image pickup element bythe optical system. The observation light is photo-electricallyconverted by the image pickup element to generate an electric signalcorresponding to the observation light, namely, an image signalcorresponding to an observation image. The image signal is transmittedas RAW data to a CCU 11201.

The CCU 11201 includes a central processing unit (CPU), a graphicsprocessing unit (GPU) or the like and integrally controls operation ofthe endoscope 11100 and a display apparatus 11202. Further, the CCU11201 receives an image signal from the camera head 11102 and performs,for the image signal, various image processes for displaying an imagebased on the image signal such as, for example, a development process(demosaic process).

The display apparatus 11202 displays thereon an image based on an imagesignal, for which the image processes have been performed by the CCU11201, under the control of the CCU 11201.

The light source apparatus 11203 includes a light source such as, forexample, a light emitting diode (LED) and supplies irradiation lightupon imaging of a surgical region to the endoscope 11100.

An inputting apparatus 11204 is an input interface for the endoscopicsurgery system 11000. A user can perform inputting of various kinds ofinformation or instruction inputting to the endoscopic surgery system11000 through the inputting apparatus 11204. For example, the user wouldinput an instruction or a like to change an image pickup condition (typeof irradiation light, magnification, focal distance or the like) by theendoscope 11100.

A treatment tool controlling apparatus 11205 controls driving of theenergy device 11112 for cautery or incision of a tissue, sealing of ablood vessel or the like. A pneumoperitoneum apparatus 11206 feeds gasinto a body cavity of the patient 11132 through the pneumoperitoneumtube 11111 to inflate the body cavity in order to secure the field ofview of the endoscope 11100 and secure the working space for thesurgeon. A recorder 11207 is an apparatus capable of recording variouskinds of information relating to surgery. A printer 11208 is anapparatus capable of printing various kinds of information relating tosurgery in various forms such as a text, an image or a graph.

It is to be noted that the light source apparatus 11203 which suppliesirradiation light when a surgical region is to be imaged to theendoscope 11100 may include a white light source which includes, forexample, an LED, a laser light source or a combination of them. Where awhite light source includes a combination of red, green, and blue (RGB)laser light sources, since the output intensity and the output timingcan be controlled with a high degree of accuracy for each color (eachwavelength), adjustment of the white balance of a picked up image can beperformed by the light source apparatus 11203. Further, in this case, iflaser beams from the respective RGB laser light sources are irradiatedtime-divisionally on an observation target and driving of the imagepickup elements of the camera head 11102 are controlled in synchronismwith the irradiation timings. Then images individually corresponding tothe R, G and B colors can be also picked up time-divisionally. Accordingto this method, a color image can be obtained even if color filters arenot provided for the image pickup element.

Further, the light source apparatus 11203 may be controlled such thatthe intensity of light to be outputted is changed for each predeterminedtime. By controlling driving of the image pickup element of the camerahead 11102 in synchronism with the timing of the change of the intensityof light to acquire images time-divisionally and synthesizing theimages, an image of a high dynamic range free from underexposed blockedup shadows and overexposed highlights can be created.

Further, the light source apparatus 11203 may be configured to supplylight of a predetermined wavelength band ready for special lightobservation. In special light observation, for example, by utilizing thewavelength dependency of absorption of light in a body tissue toirradiate light of a narrow band in comparison with irradiation lightupon ordinary observation (namely, white light), narrow band observation(narrow band imaging) of imaging a predetermined tissue such as a bloodvessel of a superficial portion of the mucous membrane or the like in ahigh contrast is performed. Alternatively, in special light observation,fluorescent observation for obtaining an image from fluorescent lightgenerated by irradiation of excitation light may be performed. Influorescent observation, it is possible to perform observation offluorescent light from a body tissue by irradiating excitation light onthe body tissue (autofluorescence observation) or to obtain afluorescent light image by locally injecting a reagent such asindocyanine green (ICG) into a body tissue and irradiating excitationlight corresponding to a fluorescent light wavelength of the reagentupon the body tissue. The light source apparatus 11203 can be configuredto supply such narrow-band light and/or excitation light suitable forspecial light observation as described above.

FIG. 36 is a block diagram depicting an example of a functionalconfiguration of the camera head 11102 and the CCU 11201 depicted inFIG. 35.

The camera head 11102 includes a lens unit 11401, an image pickup unit11402, a driving unit 11403, a communication unit 11404 and a camerahead controlling unit 11405. The CCU 11201 includes a communication unit11411, an image processing unit 11412 and a control unit 11413. Thecamera head 11102 and the CCU 11201 are connected for communication toeach other by a transmission cable 11400.

The lens unit 11401 is an optical system, provided at a connectinglocation to the lens barrel 11101. Observation light taken in from adistal end of the lens barrel 11101 is guided to the camera head 11102and introduced into the lens unit 11401. The lens unit 11401 includes acombination of a plurality of lenses including a zoom lens and afocusing lens.

The number of image pickup elements which is included by the imagepickup unit 11402 may be one (single-plate type) or a plural number(multi-plate type). Where the image pickup unit 11402 is configured asthat of the multi-plate type, for example, image signals correspondingto respective R, G and B are generated by the image pickup elements, andthe image signals may be synthesized to obtain a color image. The imagepickup unit 11402 may also be configured so as to have a pair of imagepickup elements for acquiring respective image signals for the right eyeand the left eye ready for three dimensional (3D) display. If 3D displayis performed, then the depth of a living body tissue in a surgicalregion can be comprehended more accurately by the surgeon 11131. It isto be noted that, where the image pickup unit 11402 is configured asthat of stereoscopic type, a plurality of systems of lens units 11401are provided corresponding to the individual image pickup elements.

Further, the image pickup unit 11402 may not necessarily be provided onthe camera head 11102. For example, the image pickup unit 11402 may beprovided immediately behind the objective lens in the inside of the lensbarrel 11101.

The driving unit 11403 includes an actuator and moves the zoom lens andthe focusing lens of the lens unit 11401 by a predetermined distancealong an optical axis under the control of the camera head controllingunit 11405. Consequently, the magnification and the focal point of apicked up image by the image pickup unit 11402 can be adjusted suitably.

The communication unit 11404 includes a communication apparatus fortransmitting and receiving various kinds of information to and from theCCU 11201. The communication unit 11404 transmits an image signalacquired from the image pickup unit 11402 as RAW data to the CCU 11201through the transmission cable 11400.

In addition, the communication unit 11404 receives a control signal forcontrolling driving of the camera head 11102 from the CCU 11201 andsupplies the control signal to the camera head controlling unit 11405.The control signal includes information relating to image pickupconditions such as, for example, information that a frame rate of apicked up image is designated, information that an exposure value uponimage picking up is designated and/or information that a magnificationand a focal point of a picked up image are designated.

It is to be noted that the image pickup conditions such as the framerate, exposure value, magnification or focal point may be designated bythe user or may be set automatically by the control unit 11413 of theCCU 11201 on the basis of an acquired image signal. In the latter case,an auto exposure (AE) function, an auto focus (AF) function and an autowhite balance (AWB) function are incorporated in the endoscope 11100.

The camera head controlling unit 11405 controls driving of the camerahead 11102 on the basis of a control signal from the CCU 11201 receivedthrough the communication unit 11404.

The communication unit 11411 includes a communication apparatus fortransmitting and receiving various kinds of information to and from thecamera head 11102. The communication unit 11411 receives an image signaltransmitted thereto from the camera head 11102 through the transmissioncable 11400.

Further, the communication unit 11411 transmits a control signal forcontrolling driving of the camera head 11102 to the camera head 11102.The image signal and the control signal can be transmitted by electricalcommunication, optical communication or the like.

The image processing unit 11412 performs various image processes for animage signal in the form of RAW data transmitted thereto from the camerahead 11102.

The control unit 11413 performs various kinds of control relating toimage picking up of a surgical region or the like by the endoscope 11100and display of a picked up image obtained by image picking up of thesurgical region or the like. For example, the control unit 11413 createsa control signal for controlling driving of the camera head 11102.

Further, the control unit 11413 controls, on the basis of an imagesignal for which image processes have been performed by the imageprocessing unit 11412, the display apparatus 11202 to display a pickedup image in which the surgical region or the like is imaged. Thereupon,the control unit 11413 may recognize various objects in the picked upimage using various image recognition technologies. For example, thecontrol unit 11413 can recognize a surgical tool such as forceps, aparticular living body region, bleeding, mist when the energy device11112 is used and so forth by detecting the shape, color and so forth ofedges of objects included in a picked up image. The control unit 11413may cause, when it controls the display apparatus 11202 to display apicked up image, various kinds of surgery supporting information to bedisplayed in an overlapping manner with an image of the surgical regionusing a result of the recognition. Where surgery supporting informationis displayed in an overlapping manner and presented to the surgeon11131, the burden on the surgeon 11131 can be reduced and the surgeon11131 can proceed with the surgery with certainty.

The transmission cable 11400 which connects the camera head 11102 andthe CCU 11201 to each other is an electric signal cable ready forcommunication of an electric signal, an optical fiber ready for opticalcommunication or a composite cable ready for both of electrical andoptical communications.

Here, while, in the example depicted, communication is performed bywired communication using the transmission cable 11400, thecommunication between the camera head 11102 and the CCU 11201 may beperformed by wireless communication.

The description has been given above of one example of the endoscopicsurgery system, to which the technology according to an embodiment ofthe present disclosure is applicable. The technology according to anembodiment of the present disclosure is applicable to, for example, theimage pickup unit 11402 of the configurations described above. Applyingthe technology according to an embodiment of the present disclosure tothe image pickup unit 11402 makes it possible to improve detectionaccuracy.

It is to be noted that although the endoscopic surgery system has beendescribed as an example here, the technology according to an embodimentof the present disclosure may also be applied to, for example, amicroscopic surgery system, and the like.

Application Example 5 <Example of Practical Application to Mobile Body>

The technology according to an embodiment of the present disclosure isapplicable to various products. For example, the technology according toan embodiment of the present disclosure may be achieved in the form ofan apparatus to be mounted to a mobile body of any kind. Non-limitingexamples of the mobile body may include an automobile, an electricvehicle, a hybrid electric vehicle, a motorcycle, a bicycle, anypersonal mobility device, an airplane, an unmanned aerial vehicle(drone), a vessel, a robot, a construction machine, and an agriculturalmachine (tractor).

FIG. 37 is a block diagram depicting an example of schematicconfiguration of a vehicle control system as an example of a mobile bodycontrol system to which the technology according to an embodiment of thepresent disclosure can be applied.

The vehicle control system 12000 includes a plurality of electroniccontrol units connected to each other via a communication network 12001.In the example depicted in FIG. 37, the vehicle control system 12000includes a driving system control unit 12010, a body system control unit12020, an outside-vehicle information detecting unit 12030, anin-vehicle information detecting unit 12040, and an integrated controlunit 12050. In addition, a microcomputer 12051, a sound/image outputsection 12052, and a vehicle-mounted network interface (I/F) 12053 areillustrated as a functional configuration of the integrated control unit12050.

The driving system control unit 12010 controls the operation of devicesrelated to the driving system of the vehicle in accordance with variouskinds of programs. For example, the driving system control unit 12010functions as a control device for a driving force generating device forgenerating the driving force of the vehicle, such as an internalcombustion engine, a driving motor, or the like, a driving forcetransmitting mechanism for transmitting the driving force to wheels, asteering mechanism for adjusting the steering angle of the vehicle, abraking device for generating the braking force of the vehicle, and thelike.

The body system control unit 12020 controls the operation of variouskinds of devices provided to a vehicle body in accordance with variouskinds of programs. For example, the body system control unit 12020functions as a control device for a keyless entry system, a smart keysystem, a power window device, or various kinds of lamps such as aheadlamp, a backup lamp, a brake lamp, a turn signal, a fog lamp, or thelike. In this case, radio waves transmitted from a mobile device as analternative to a key or signals of various kinds of switches can beinput to the body system control unit 12020. The body system controlunit 12020 receives these input radio waves or signals, and controls adoor lock device, the power window device, the lamps, or the like of thevehicle.

The outside-vehicle information detecting unit 12030 detects informationabout the outside of the vehicle including the vehicle control system12000. For example, the outside-vehicle information detecting unit 12030is connected with an imaging section 12031. The outside-vehicleinformation detecting unit 12030 makes the imaging section 12031 imagean image of the outside of the vehicle, and receives the imaged image.On the basis of the received image, the outside-vehicle informationdetecting unit 12030 may perform processing of detecting an object suchas a human, a vehicle, an obstacle, a sign, a character on a roadsurface, or the like, or processing of detecting a distance thereto.

The imaging section 12031 is an optical sensor that receives light, andwhich outputs an electric signal corresponding to a received lightamount of the light. The imaging section 12031 can output the electricsignal as an image, or can output the electric signal as informationabout a measured distance. In addition, the light received by theimaging section 12031 may be visible light, or may be invisible lightsuch as infrared rays or the like.

The in-vehicle information detecting unit 12040 detects informationabout the inside of the vehicle. The in-vehicle information detectingunit 12040 is, for example, connected with a driver state detectingsection 12041 that detects the state of a driver. The driver statedetecting section 12041, for example, includes a camera that images thedriver. On the basis of detection information input from the driverstate detecting section 12041, the in-vehicle information detecting unit12040 may calculate a degree of fatigue of the driver or a degree ofconcentration of the driver, or may determine whether the driver isdozing.

The microcomputer 12051 can calculate a control target value for thedriving force generating device, the steering mechanism, or the brakingdevice on the basis of the information about the inside or outside ofthe vehicle which information is obtained by the outside-vehicleinformation detecting unit 12030 or the in-vehicle information detectingunit 12040, and output a control command to the driving system controlunit 12010. For example, the microcomputer 12051 can perform cooperativecontrol intended to implement functions of an advanced driver assistancesystem (ADAS) which functions include collision avoidance or shockmitigation for the vehicle, following driving based on a followingdistance, vehicle speed maintaining driving, a warning of collision ofthe vehicle, a warning of deviation of the vehicle from a lane, or thelike.

In addition, the microcomputer 12051 can perform cooperative controlintended for automatic driving, which makes the vehicle to travelautonomously without depending on the operation of the driver, or thelike, by controlling the driving force generating device, the steeringmechanism, the braking device, or the like on the basis of theinformation about the outside or inside of the vehicle which informationis obtained by the outside-vehicle information detecting unit 12030 orthe in-vehicle information detecting unit 12040.

In addition, the microcomputer 12051 can output a control command to thebody system control unit 12020 on the basis of the information about theoutside of the vehicle which information is obtained by theoutside-vehicle information detecting unit 12030. For example, themicrocomputer 12051 can perform cooperative control intended to preventa glare by controlling the headlamp so as to change from a high beam toa low beam, for example, in accordance with the position of a precedingvehicle or an oncoming vehicle detected by the outside-vehicleinformation detecting unit 12030.

The sound/image output section 12052 transmits an output signal of atleast one of a sound and an image to an output device capable ofvisually or auditorily notifying information to an occupant of thevehicle or the outside of the vehicle. In the example of FIG. 13, anaudio speaker 12061, a display section 12062, and an instrument panel12063 are illustrated as the output device. The display section 12062may, for example, include at least one of an on-board display and ahead-up display.

FIG. 38 is a diagram depicting an example of the installation positionof the imaging section 12031.

In FIG. 38, the imaging section 12031 includes imaging sections 12101,12102, 12103, 12104, and 12105.

The imaging sections 12101, 12102, 12103, 12104, and 12105 are, forexample, disposed at positions on a front nose, sideview mirrors, a rearbumper, and a back door of the vehicle 12100 as well as a position on anupper portion of a windshield within the interior of the vehicle. Theimaging section 12101 provided to the front nose and the imaging section12105 provided to the upper portion of the windshield within theinterior of the vehicle obtain mainly an image of the front of thevehicle 12100. The imaging sections 12102 and 12103 provided to thesideview mirrors obtain mainly an image of the sides of the vehicle12100. The imaging section 12104 provided to the rear bumper or the backdoor obtains mainly an image of the rear of the vehicle 12100. Theimaging section 12105 provided to the upper portion of the windshieldwithin the interior of the vehicle is used mainly to detect a precedingvehicle, a pedestrian, an obstacle, a signal, a traffic sign, a lane, orthe like.

Incidentally, FIG. 38 depicts an example of photographing ranges of theimaging sections 12101 to 12104. An imaging range 12111 represents theimaging range of the imaging section 12101 provided to the front nose.Imaging ranges 12112 and 12113 respectively represent the imaging rangesof the imaging sections 12102 and 12103 provided to the sideviewmirrors. An imaging range 12114 represents the imaging range of theimaging section 12104 provided to the rear bumper or the back door. Abird's-eye image of the vehicle 12100 as viewed from above is obtainedby superimposing image data imaged by the imaging sections 12101 to12104, for example.

At least one of the imaging sections 12101 to 12104 may have a functionof obtaining distance information. For example, at least one of theimaging sections 12101 to 12104 may be a stereo camera constituted of aplurality of imaging elements, or may be an imaging element havingpixels for phase difference detection.

For example, the microcomputer 12051 can determine a distance to eachthree-dimensional object within the imaging ranges 12111 to 12114 and atemporal change in the distance (relative speed with respect to thevehicle 12100) on the basis of the distance information obtained fromthe imaging sections 12101 to 12104, and thereby extract, as a precedingvehicle, a nearest three-dimensional object in particular that ispresent on a traveling path of the vehicle 12100 and which travels insubstantially the same direction as the vehicle 12100 at a predeterminedspeed (for example, equal to or more than 0 km/hour). Further, themicrocomputer 12051 can set a following distance to be maintained infront of a preceding vehicle in advance, and perform automatic brakecontrol (including following stop control), automatic accelerationcontrol (including following start control), or the like. It is thuspossible to perform cooperative control intended for automatic drivingthat makes the vehicle travel autonomously without depending on theoperation of the driver or the like.

For example, the microcomputer 12051 can classify three-dimensionalobject data on three-dimensional objects into three-dimensional objectdata of a two-wheeled vehicle, a standard-sized vehicle, a large-sizedvehicle, a pedestrian, a utility pole, and other three-dimensionalobjects on the basis of the distance information obtained from theimaging sections 12101 to 12104, extract the classifiedthree-dimensional object data, and use the extracted three-dimensionalobject data for automatic avoidance of an obstacle. For example, themicrocomputer 12051 identifies obstacles around the vehicle 12100 asobstacles that the driver of the vehicle 12100 can recognize visuallyand obstacles that are difficult for the driver of the vehicle 12100 torecognize visually. Then, the microcomputer 12051 determines a collisionrisk indicating a risk of collision with each obstacle. In a situationin which the collision risk is equal to or higher than a set value andthere is thus a possibility of collision, the microcomputer 12051outputs a warning to the driver via the audio speaker 12061 or thedisplay section 12062, and performs forced deceleration or avoidancesteering via the driving system control unit 12010. The microcomputer12051 can thereby assist in driving to avoid collision.

At least one of the imaging sections 12101 to 12104 may be an infraredcamera that detects infrared rays. The microcomputer 12051 can, forexample, recognize a pedestrian by determining whether or not there is apedestrian in imaged images of the imaging sections 12101 to 12104. Suchrecognition of a pedestrian is, for example, performed by a procedure ofextracting characteristic points in the imaged images of the imagingsections 12101 to 12104 as infrared cameras and a procedure ofdetermining whether or not it is the pedestrian by performing patternmatching processing on a series of characteristic points representingthe contour of the object. When the microcomputer 12051 determines thatthere is a pedestrian in the imaged images of the imaging sections 12101to 12104, and thus recognizes the pedestrian, the sound/image outputsection 12052 controls the display section 12062 so that a squarecontour line for emphasis is displayed so as to be superimposed on therecognized pedestrian. The sound/image output section 12052 may alsocontrol the display section 12062 so that an icon or the likerepresenting the pedestrian is displayed at a desired position.

An example of the vehicle control system to which the technologyaccording to an embodiment of the present disclosure may be applied hasbeen described above. The technology according to an embodiment of thepresent disclosure may be applied to the imaging section 12031 out ofthe configurations described above. Specifically, the solid-stateimaging device 1 in FIG. 32 is applicable to the imaging section 12031.Applying the technology according to an embodiment of the presentdisclosure to the imaging section 12031 makes it possible to obtain acaptured image that is easier to see. This makes it possible to decreasefatigue of a driver.

Description has been given hereinabove referring to the embodiments,etc.; however, the content of the present disclosure is not limited tothe foregoing embodiments, etc., and various modifications may be made.For example, in the foregoing embodiment, etc., the solid-state imagingelement 10, etc. has a configuration in which the organic photoelectricconversion section 11G that detects green light, and the organicphotoelectric conversion section 20 that detects green light and theinorganic photoelectric conversion sections 32B and 32R that detect,respectively, blue light and red light are stacked. However, the contentof the present disclosure is not limited to such a structure. In otherwords, red light or blue light may be detected in the organicphotoelectric conversion section, and green light may be detected in theinorganic photoelectric conversion section.

In addition, the number or ratio of the organic photoelectric conversionsection and the inorganic photoelectric conversion sections are notlimited; two or more organic photoelectric conversion sections may beprovided. For example, the present technology achieves effects similarto those of the foregoing embodiments, etc. also in a solid-stateimaging element of a vertical spectroscopic type in which a redphotoelectric conversion section, a green photoelectric conversionsection, and a blue photoelectric conversion section, that includeorganic semiconductor materials being able to selectively absorb lightbeams in predetermined respective wavelength regions, are stacked inthis order on a substrate with an insulating layer interposedtherebetween. In addition, the present technology achieves effectssimilar to those of the foregoing embodiments, etc. also in asolid-state imaging element in which an organic photoelectric conversionsection and an inorganic photoelectric conversion section are arrangedside by side along a substrate plane.

Further, the configuration of the solid-state imaging element of thepresent disclosure is not limited to the combinations illustrated in theforegoing embodiments, etc. For example, the solid-state imaging elementmay include the transfer electrode 21C, the discharge electrode 21D, andthe shielding electrode 21E. In addition, the accumulation electrode 21Bmay be formed to be divided into two or three or more.

In addition, the solid-state imaging element and the solid-state imagingdevice of the present disclosure do not need to include all of theconstituent elements described in the foregoing embodiments, etc., andmay include any other layer on the contrary.

The effects described in the foregoing embodiments, etc. are merelyexemplary, and may be other effects or may further include othereffects.

It is to be noted that the present disclosure may include the followingconfigurations.

(1)

A solid-state imaging element including:

a photoelectric conversion layer;

a first electrode and a second electrode opposed to each other with thephotoelectric conversion layer interposed therebetween;

a semiconductor layer provided between the first electrode and thephotoelectric conversion layer;

an accumulation electrode opposed to the photoelectric conversion layerwith the semiconductor layer interposed therebetween;

an insulating film provided between the accumulation electrode and thesemiconductor layer; and

a barrier layer provided between the semiconductor layer and thephotoelectric conversion layer.

(2)

A solid-state imaging element including:

a photoelectric conversion layer;

a first electrode and a second electrode opposed to each other with thephotoelectric conversion layer interposed therebetween;

a semiconductor layer provided between the first electrode and thephotoelectric conversion layer, the semiconductor layer having apotential barrier at a junction plane with respect to the photoelectricconversion layer;

an accumulation electrode opposed to the photoelectric conversion layerwith the semiconductor layer interposed therebetween; and

an insulating film provided between the accumulation electrode and thesemiconductor layer.

(3)

The solid-state imaging element according to (1) or (2), in which

the photoelectric conversion layer includes an organic semiconductormaterial, and

the semiconductor layer includes a semiconductor material havingmobility higher than mobility of the organic semiconductor material.

(4)

The solid-state imaging element according to (1), further including asemiconductor substrate having a first surface and a second surface thatare opposed to each other, in which

the first electrode, the semiconductor layer, the barrier layer, thephotoelectric conversion layer, and the second electrode are provided inthis order on the first surface of the semiconductor substrate.

(5)

The solid-state imaging element according to any one of (1) to (3),further including:

a semiconductor substrate having a first surface and a second surfacethat are opposed to each other; and

a multilayer wiring line provided between the second surface of thesemiconductor substrate and the first electrode.

(6)

The solid-state imaging element according to (4) or (5), furtherincluding an inorganic photoelectric conversion section provided in thesemiconductor substrate.

(7)

The solid-state imaging element according to any one of (1) to (6),further including a transfer electrode provided opposed to thesemiconductor layer with the insulating film interposed therebetween,the transfer electrode controlling movement of signal charges in thesemiconductor layer.

(8)

The solid-state imaging element according to any one of (1) to (7),further including a discharge electrode provided apart from the firstelectrode and electrically coupled to the semiconductor layer.

(9)

The solid-state imaging element according to any one of (1) to (8),further including a light-shielding film that covers the first electrodewith the photoelectric conversion layer interposed therebetween.

(10)

The solid-state imaging element according to (1), in which the barrierlayer includes silicon oxide, silicon nitride, silicon oxynitride, or anorganic material.

(11)

A solid-state imaging device including a plurality of solid-stateimaging elements, the solid-state imaging elements each including

a photoelectric conversion layer,

a first electrode and a second electrode opposed to each other with thephotoelectric conversion layer interposed therebetween,

a semiconductor layer provided between the first electrode and thephotoelectric conversion layer,

an accumulation electrode opposed to the photoelectric conversion layerwith the semiconductor layer interposed therebetween,

an insulating film provided between the accumulation electrode and thesemiconductor layer, and

a barrier layer provided between the semiconductor layer and thephotoelectric conversion layer.

(12)

A solid-state imaging device including a plurality of solid-stateimaging elements, the solid-state imaging elements each including

a photoelectric conversion layer,

a first electrode and a second electrode opposed to each other with thephotoelectric conversion layer interposed therebetween,

a semiconductor layer provided between the first electrode and thephotoelectric conversion layer, the semiconductor layer having apotential barrier at a junction plane with respect to the photoelectricconversion layer,

an accumulation electrode opposed to the photoelectric conversion layerwith the semiconductor layer interposed therebetween, and

an insulating film provided between the accumulation electrode and thesemiconductor layer.

(13)

The solid-state imaging device according to (11) or (12), furtherincluding a shielding electrode opposed to the semiconductor layer withthe insulating film interposed therebetween, the shielding electrodebeing arranged between the accumulation electrodes adjacent to eachother.

(14)

The solid-state imaging device according to any one of (11) to (13),including a plurality of pixels in which the respective solid-stateimaging elements are provided, in which the semiconductor layer isprovided separately for each of the pixels.

(15)

The solid-state imaging device according to any one of (11) to (14),including a plurality of pixels in which the respective solid-stateimaging elements are provided, in which the photoelectric conversionlayer is provided separately for each of the pixels.

This application claims the benefit of Japanese Priority PatentApplication JP2018-50808 filed with the Japan Patent Office on Mar. 19,2018, the entire contents of which are incorporated herein by reference.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations, and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

What is claimed is:
 1. A solid-state imaging element comprising: aphotoelectric conversion layer; a first electrode and a second electrodeopposed to each other with the photoelectric conversion layer interposedtherebetween; a semiconductor layer provided between the first electrodeand the photoelectric conversion layer; an accumulation electrodeopposed to the photoelectric conversion layer with the semiconductorlayer interposed therebetween; an insulating film provided between theaccumulation electrode and the semiconductor layer; and a barrier layerprovided between the semiconductor layer and the photoelectricconversion layer.
 2. A solid-state imaging element comprising: aphotoelectric conversion layer; a first electrode and a second electrodeopposed to each other with the photoelectric conversion layer interposedtherebetween; a semiconductor layer provided between the first electrodeand the photoelectric conversion layer, the semiconductor layer having apotential barrier at a junction plane with respect to the photoelectricconversion layer; an accumulation electrode opposed to the photoelectricconversion layer with the semiconductor layer interposed therebetween;and an insulating film provided between the accumulation electrode andthe semiconductor layer.
 3. The solid-state imaging element according toclaim 1, wherein the photoelectric conversion layer includes an organicsemiconductor material, and the semiconductor layer includes asemiconductor material having mobility higher than mobility of theorganic semiconductor material.
 4. The solid-state imaging elementaccording to claim 1, further comprising a semiconductor substratehaving a first surface and a second surface that are opposed to eachother, wherein the first electrode, the semiconductor layer, the barrierlayer, the photoelectric conversion layer, and the second electrode areprovided in this order on the first surface of the semiconductorsubstrate.
 5. The solid-state imaging element according to claim 1,further comprising: a semiconductor substrate having a first surface anda second surface that are opposed to each other; and a multilayer wiringline provided between the second surface of the semiconductor substrateand the first electrode.
 6. The solid-state imaging element according toclaim 4, further comprising an inorganic photoelectric conversionsection provided in the semiconductor substrate.
 7. The solid-stateimaging element according to claim 1, further comprising a transferelectrode provided opposed to the semiconductor layer with theinsulating film interposed therebetween, the transfer electrodecontrolling movement of signal charges in the semiconductor layer. 8.The solid-state imaging element according to claim 1, further comprisinga discharge electrode provided apart from the first electrode andelectrically coupled to the semiconductor layer.
 9. The solid-stateimaging element according to claim 1, further comprising alight-shielding film that covers the first electrode with thephotoelectric conversion layer interposed therebetween.
 10. Thesolid-state imaging element according to claim 1, wherein the barrierlayer includes silicon oxide, silicon nitride, silicon oxynitride, or anorganic material.
 11. A solid-state imaging device comprising aplurality of solid-state imaging elements, the solid-state imagingelements each including a photoelectric conversion layer, a firstelectrode and a second electrode opposed to each other with thephotoelectric conversion layer interposed therebetween, a semiconductorlayer provided between the first electrode and the photoelectricconversion layer, an accumulation electrode opposed to the photoelectricconversion layer with the semiconductor layer interposed therebetween,an insulating film provided between the accumulation electrode and thesemiconductor layer, and a barrier layer provided between thesemiconductor layer and the photoelectric conversion layer.
 12. Asolid-state imaging device comprising a plurality of solid-state imagingelements, the solid-state imaging elements each including aphotoelectric conversion layer, a first electrode and a second electrodeopposed to each other with the photoelectric conversion layer interposedtherebetween, a semiconductor layer provided between the first electrodeand the photoelectric conversion layer, the semiconductor layer having apotential barrier at a junction plane with respect to the photoelectricconversion layer, an accumulation electrode opposed to the photoelectricconversion layer with the semiconductor layer interposed therebetween,and an insulating film provided between the accumulation electrode andthe semiconductor layer.
 13. The solid-state imaging device according toclaim 11, further comprising a shielding electrode opposed to thesemiconductor layer with the insulating film interposed therebetween,the shielding electrode being arranged between the accumulationelectrodes adjacent to each other.
 14. The solid-state imaging deviceaccording to claim 11, comprising a plurality of pixels in which therespective solid-state imaging elements are provided, wherein thesemiconductor layer is provided separately for each of the pixels. 15.The solid-state imaging device according to claim 11, comprising aplurality of pixels in which the respective solid-state imaging elementsare provided, wherein the photoelectric conversion layer is providedseparately for each of the pixels.